Perfectly matched multiscale simulations
NASA Astrophysics Data System (ADS)
Liu, Xiaohu
In this dissertation, the Perfectly Matched Multiscale Simulations (PMMS), a method of discrete-to-continuum multiscale scale computation is studied, revised and extended. In particular, the role of the Perfectly Matched Layer (PML) in PMMS is carefully studied. We show that instead of following the PML theory of continuum, the PML equations of motion in PMMS can be derived by stretching the inter-atomic equilibrium distance. As a result, the displacement solution in the PML region has the desired spatial damping property. It is also shown that the dispersion relationship in the PML region is different from the one in the original lattice. And a reflection coefficient is computed. We also incorporate the local Quasicontinuum (QC) theory with the cohesive Finite Element (FE) method to form a cohesive QC scheme which can deal with arbitrary discontinuities. This idea is built into the PMMS method to simulate a moving screw dislocation. The second part of the dissertation is to extend PMMS to finite temperature. A multiscale thermodynamics is proposed based on the idea of distributed coarse scale thermostats. Each coarse scale node is viewed as a thermostat and has part of atoms associated with it. The atomic motion at the fine scale level is governed by the Nose-Hoover dynamics. At the coarse scale, the expression of a coarse-grained Helmholtz free energy is derived and coupled thermo-mechanical equations are formulated based on it. With the proposed framework, the finite-temperature PMMS method is capable of simulating problems with drastic temperature change. Several numerical examples are computed to validate the method.
NASA Astrophysics Data System (ADS)
Kerr, Robert
2008-09-01
As a child I always used to wonder how someone could be described as a "perfect stranger". Not only did I not know any strangers (by definition), I also didn't really see how anyone could be called perfect - that seemed a bridge too far. Nowadays, however, in my early dotage/mid-life crisis/eternally youthful existence (depending on whether you are talking to my friends, family or me) I begin to see that perhaps at last I have achieved a level of perfection not anticipated in my youth. You see, I have almost completely transmogrified myself from a real physics teacher into a pretend sociologist. I am now, and intend to continue to be for some time, a perfect fraud.
Perfectly matched layer based multilayer absorbers
NASA Astrophysics Data System (ADS)
Stefaniuk, Tomasz; Stolarek, Marcin; Pastuszczak, Anna; Wróbel, Piotr; Wieciech, Bartosz; Antosiewicz, Tomasz J.; Kotyński, Rafał
2015-05-01
Broadband layered absorbers are analysed theoretically and experimentally. A genetic algorithm is used to opti- mize broadband and wide-angle of incidence metal-dielectric layered absorbers. An approximate representation of the perfectly matched layer with a spatially varied absorption strength is discussed. The PML is realised as a stack of uniform and isotropic metamaterial layers with permittivieties and permeabilities given from the effective medium theory. This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML).1 We compare the re ection properties of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional.
Asymmetric perfectly matched layer for the absorption of waves
Vay, Jean-Luc
2002-02-10
The Perfectly Matched Layer (PML) has become a standard for comparison in the techniques that have been developed to close the system of Maxwell equations (more generally wave equations) when simulating an open system. The original Berenger PML formulation relies on a split version of Maxwell equations with numerical electric and magnetic conductivities. They present here an extension of this formulation which introduces counterparts of the electric and magnetic conductivities affecting the term which is spatially differentiated in the equations. they phase velocity along each direction is also multiplied by an additional coefficient. They show that, under certain constraints on the additional numerical coefficients, this ''medium'' does not generate any reflection at any angle and any frequency and is then a Perfectly Matched Layer. Technically it is a super-set of Berenger's PML to which it reduces for a specific set of parameters and like it, it is anisotropic. However, unlike the PML, it introduces some asymmetry in the absorption rate and is therefore labeled an APML for Asymmetric Perfectly Matched Layer. They present here the numerical considerations that have led them to introduce such a medium as well as its theory. Several finite-different numerical implementations are derived (in one, two and three dimensions) and the performance of the APML is contrasted with that of the PML in one and two dimensions. Using plane wave analysis, they show that the APML implementations lead to higher absorption rates than the considered PML implementations. Although they have considered in this paper the finite-different discretization of Maxwell-like equations only, the APML system of equations may be used with other discretization schemes, such as finite-elements, and may be applied to other equations, for applications beyond electromagnetics.
A PERFECT MATCH CONDITION FOR POINT-SET MATCHING PROBLEMS USING THE OPTIMAL MASS TRANSPORT APPROACH
CHEN, PENGWEN; LIN, CHING-LONG; CHERN, I-LIANG
2013-01-01
We study the performance of optimal mass transport-based methods applied to point-set matching problems. The present study, which is based on the L2 mass transport cost, states that perfect matches always occur when the product of the point-set cardinality and the norm of the curl of the non-rigid deformation field does not exceed some constant. This analytic result is justified by a numerical study of matching two sets of pulmonary vascular tree branch points whose displacement is caused by the lung volume changes in the same human subject. The nearly perfect match performance verifies the effectiveness of this mass transport-based approach. PMID:23687536
Improved and perfect actions in discrete gravity
Bahr, Benjamin; Dittrich, Bianca
2009-12-15
We consider the notion of improved and perfect actions within Regge calculus. These actions are constructed in such a way that they - although being defined on a triangulation - reproduce the continuum dynamics exactly, and therefore capture the gauge symmetries of general relativity. We construct the perfect action in three dimensions with a cosmological constant, and in four dimensions for one simplex. We conclude with a discussion about Regge calculus with curved simplices, which arises naturally in this context.
AN FDTD ALGORITHM WITH PERFECTLY MATCHED LAYERS FOR CONDUCTIVE MEDIA. (R825225)
We extend Berenger's perfectly matched layers (PML) to conductive media. A finite-difference-time-domain (FDTD) algorithm with PML as an absorbing boundary condition is developed for solutions of Maxwell's equations in inhomogeneous, conductive media. For a perfectly matched laye...
NASA Technical Reports Server (NTRS)
Garai, Anirban; Diosady, Laslo T.; Murman, Scott M.; Madavan, Nateri K.
2016-01-01
The perfectly matched layer (PML) technique is developed in the context of a high- order spectral-element Discontinuous-Galerkin (DG) method. The technique is applied to a range of test cases and is shown to be superior compared to other approaches, such as those based on using characteristic boundary conditions and sponge layers, for treating the inflow and outflow boundaries of computational domains. In general, the PML technique improves the quality of the numerical results for simulations of practical flow configurations, but it also exhibits some instabilities for large perturbations. A preliminary analysis that attempts to understand the source of these instabilities is discussed.
The perfect match: Do criminal stereotypes bias forensic evidence analysis?
Smalarz, Laura; Madon, Stephanie; Yang, Yueran; Guyll, Max; Buck, Sarah
2016-08-01
This research provided the first empirical test of the hypothesis that stereotypes bias evaluations of forensic evidence. A pilot study (N = 107) assessed the content and consensus of 20 criminal stereotypes by identifying perpetrator characteristics (e.g., sex, race, age, religion) that are stereotypically associated with specific crimes. In the main experiment (N = 225), participants read a mock police incident report involving either a stereotyped crime (child molestation) or a nonstereotyped crime (identity theft) and judged whether a suspect's fingerprint matched a fingerprint recovered at the crime scene. Accompanying the suspect's fingerprint was personal information about the suspect of the type that is routinely available to fingerprint analysts (e.g., race, sex) and which could activate a stereotype. Participants most often perceived the fingerprints to match when the suspect fit the criminal stereotype, even though the prints did not actually match. Moreover, participants appeared to be unaware of the extent to which a criminal stereotype had biased their evaluations. These findings demonstrate that criminal stereotypes are a potential source of bias in forensic evidence analysis and suggest that suspects who fit criminal stereotypes may be disadvantaged over the course of the criminal justice process. (PsycINFO Database Record PMID:27149288
NASA Technical Reports Server (NTRS)
Goodrich, John W.
2009-01-01
In this paper we show by means of numerical experiments that the error introduced in a numerical domain because of a Perfectly Matched Layer or Damping Layer boundary treatment can be controlled. These experimental demonstrations are for acoustic propagation with the Linearized Euler Equations with both uniform and steady jet flows. The propagating signal is driven by a time harmonic pressure source. Combinations of Perfectly Matched and Damping Layers are used with different damping profiles. These layer and profile combinations allow the relative error introduced by a layer to be kept as small as desired, in principle. Tradeoffs between error and cost are explored.
NASA Astrophysics Data System (ADS)
Martin, Roland; Komatitsch, Dimitri; Bruthiaux, Emilien; Gedney, Stephen D.
2010-05-01
We present and discuss here two different unsplit formulations of the frequency shift PML based on convolution or non convolution integrations of auxiliary memory variables. Indeed, the Perfectly Matched Layer absorbing boundary condition has proven to be very efficient from a numerical point of view for the elastic wave equation to absorb both body waves with non-grazing incidence and surface waves. However, at grazing incidence the classical discrete Perfectly Matched Layer method suffers from large spurious reflections that make it less efficient for instance in the case of very thin mesh slices, in the case of sources located very close to the edge of the mesh, and/or in the case of receivers located at very large offset. In [1] we improve the Perfectly Matched Layer at grazing incidence for the seismic wave equation based on an unsplit convolution technique. This improved PML has a cost that is similar in terms of memory storage to that of the classical PML. We illustrate the efficiency of this improved Convolutional Perfectly Matched Layer based on numerical benchmarks using a staggered finite-difference method on a very thin mesh slice for an isotropic material and show that results are significantly improved compared with the classical Perfectly Matched Layer technique. We also show that, as the classical model, the technique is intrinsically unstable in the case of some anisotropic materials. In this case, retaining an idea of [2], this has been stabilized by adding correction terms adequately along any coordinate axis [3]. More specifically this has been applied to the spectral-element method based on a hybrid first/second order time integration scheme in which the Newmark time marching scheme allows us to match perfectly at the base of the absorbing layer a velocity-stress formulation in the PML and a second order displacement formulation in the inner computational domain.Our CPML unsplit formulation has the advantage to reduce the memory storage of CPML
Najafi-Yazdi, A; Mongeau, L
2012-09-15
The Lattice Boltzmann Method (LBM) is a well established computational tool for fluid flow simulations. This method has been recently utilized for low Mach number computational aeroacoustics. Robust and nonreflective boundary conditions, similar to those used in Navier-Stokes solvers, are needed for LBM-based aeroacoustics simulations. The goal of the present study was to develop an absorbing boundary condition based on the perfectly matched layer (PML) concept for LBM. The derivation of formulations for both two and three dimensional problems are presented. The macroscopic behavior of the new formulation is discussed. The new formulation was tested using benchmark acoustic problems. The perfectly matched layer concept appears to be very well suited for LBM, and yielded very low acoustic reflection factor. PMID:23526050
Najafi-Yazdi, A.; Mongeau, L.
2012-01-01
The Lattice Boltzmann Method (LBM) is a well established computational tool for fluid flow simulations. This method has been recently utilized for low Mach number computational aeroacoustics. Robust and nonreflective boundary conditions, similar to those used in Navier-Stokes solvers, are needed for LBM-based aeroacoustics simulations. The goal of the present study was to develop an absorbing boundary condition based on the perfectly matched layer (PML) concept for LBM. The derivation of formulations for both two and three dimensional problems are presented. The macroscopic behavior of the new formulation is discussed. The new formulation was tested using benchmark acoustic problems. The perfectly matched layer concept appears to be very well suited for LBM, and yielded very low acoustic reflection factor. PMID:23526050
NASA Astrophysics Data System (ADS)
Bermúdez, A.; Hervella-Nieto, L.; Prieto, A.; Rodríguez, R.
2007-05-01
We introduce an optimal bounded perfectly matched layer (PML) technique by choosing a particular absorbing function with unbounded integral. With this choice, spurious reflections are avoided, even though the thickness of the layer is finite. We show that such choice is easy to implement in a finite element method and overcomes the dependency of parameters for the discrete problem. Finally, its efficiency and accuracy are illustrated with some numerical tests.
Improving Our Teaching: Practice Makes Perfect.
ERIC Educational Resources Information Center
Druger, Marvin
2001-01-01
Discusses effective ways to improve teaching and focuses on self awareness, peer videotaping, and student feedback. Explains the practice cycle with five elements: set goal, practice, feedback, reflection, and adjustment. (YDS)
The Analysis and Construction of Perfectly Matched Layers for the Linearized Euler Equations
NASA Technical Reports Server (NTRS)
Hesthaven, J. S.
1997-01-01
We present a detailed analysis of a recently proposed perfectly matched layer (PML) method for the absorption of acoustic waves. The split set of equations is shown to be only weakly well-posed, and ill-posed under small low order perturbations. This analysis provides the explanation for the stability problems associated with the split field formulation and illustrates why applying a filter has a stabilizing effect. Utilizing recent results obtained within the context of electromagnetics, we develop strongly well-posed absorbing layers for the linearized Euler equations. The schemes are shown to be perfectly absorbing independent of frequency and angle of incidence of the wave in the case of a non-convecting mean flow. In the general case of a convecting mean flow, a number of techniques is combined to obtain a absorbing layers exhibiting PML-like behavior. The efficacy of the proposed absorbing layers is illustrated though computation of benchmark problems in aero-acoustics.
Sensitive Radio-Frequency Measurements of a Quantum Dot by Tuning to Perfect Impedance Matching
NASA Astrophysics Data System (ADS)
Ares, N.; Schupp, F. J.; Mavalankar, A.; Rogers, G.; Griffiths, J.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A.; Smith, C. G.; Cottet, A.; Briggs, G. A. D.; Laird, E. A.
2016-03-01
Electrical readout of spin qubits requires fast and sensitive measurements, which are hindered by poor impedance matching to the device. We demonstrate perfect impedance matching in a radio-frequency readout circuit, using voltage-tunable varactors to cancel out parasitic capacitances. An optimized capacitance sensitivity of 1.6 aF /√{Hz } is achieved at a maximum source-drain bias of 170 -μ V root-mean-square and with a bandwidth of 18 MHz. Coulomb blockade in a quantum-dot is measured in both conductance and capacitance, and the two contributions are found to be proportional as expected from a quasistatic tunneling model. We benchmark our results against the requirements for single-shot qubit readout using quantum capacitance, a goal that has so far been elusive.
On absorbing boundary conditions for linearized Euler equations by a perfectly matched layer
NASA Technical Reports Server (NTRS)
Hu, Fang Q.
1995-01-01
Recently, Berenger introduced a Perfectly Matched Layer (PML) technique for absorbing electromagnetic waves. In the present paper, a perfectly matched layer is proposed for absorbing out-going two-dimensional waves in a uniform mean flow, generated by linearized Euler equations. It is well known that the linearized Euler equations support acoustic waves, which travel with the speed of sound relative to the mean flow, and vorticity and entropy waves, which travel with the mean flow. The PML equations to be used at a region adjacent to the artificial boundary for absorbing these linear waves are defined. Plane waves solutions to the PML equations are developed and wave propagation and absorption properties are given. It is shown that the theoretical reflection coefficients at an interface between the Euler and PML domains are zero, independent of the angle of incidence and frequency of the waves. As such, the present study points out a possible alternative approach for absorbing out-going waves of the Euler equations with little or no reflection in computation. Numerical examples that demonstrate the validity of the proposed PML equations are also presented.
Loop calculus and bootstrap-belief propagation for perfect matchings on arbitrary graphs
NASA Astrophysics Data System (ADS)
Chertkov, M.; Gelfand, A.; Shin, J.
2013-12-01
This manuscript discusses computation of the Partition Function (PF) and the Minimum Weight Perfect Matching (MWPM) on arbitrary, non-bipartite graphs. We present two novel problem formulations - one for computing the PF of a Perfect Matching (PM) and one for finding MWPMs - that build upon the inter-related Bethe Free Energy (BFE), Belief Propagation (BP), Loop Calculus (LC), Integer Linear Programming and Linear Programming frameworks. First, we describe an extension of the LC framework to the PM problem. The resulting formulas, coined (fractional) Bootstrap-BP, express the PF of the original model via the BFE of an alternative PM problem. We then study the zero-temperature version of this Bootstrap-BP formula for approximately solving the MWPM problem. We do so by leveraging the Bootstrap-BP formula to construct a sequence of MWPM problems, where each new problem in the sequence is formed by contracting odd-sized cycles (or blossoms) from the previous problem. This Bootstrap-and-Contract procedure converges reliably and generates an empirically tight upper bound for the MWPM. We conclude by discussing the relationship between our iterative procedure and the famous Blossom Algorithm of Edmonds '65 and demonstrate the performance of the Bootstrap-and-Contract approach on a variety of weighted PM problems.
The Effectiveness of the Perfectly Matched Layer in Fluid-Structure Interaction Problems
NASA Astrophysics Data System (ADS)
Zhang, Lucy; Yang, Jubiao
2015-11-01
It is well recognized that spurious reflections on computational domain boundaries can have contamination of the flow field when solving fluid and/or wave equations. The effects are even more pronounced in fluid-structure interaction (FSI) problems, since the solid responses may be distorted due to the contaminated flow field. In this work, we implemented the perfectly matched layer (PML) technique and applied it in our fully-coupled immersed finite element method (IFEM), where Navier-Stokes equations are solved in the fluid domain with finite element method. With PML included as an absorbing layer it successfully absorbs outgoing waves from the interior of the computational domain and therefore keeps them from reflecting back from the computational boundary. Validation cases are shown to demonstrate the effectiveness of the PML in pure computational fluid dynamics cases, and then followed by FSI problems.
Feng, Xue; Ben Tahar, Mabrouk; Baccouche, Ryan
2016-01-01
This paper presents a solution for aero-acoustic problems using the Galbrun equation in the time domain with a non-uniform steady mean flow in a two-dimensional coordinate system and the perfectly matched layer technique as the boundary conditions corresponding to an unbounded domain. This approach is based on an Eulerian-Lagrangian description corresponding to a wave equation written only in terms of the Lagrangian perturbation of the displacement. It is an alternative to the Linearized Euler Equations for solving aero-acoustic problems. The Galbrun equation is solved using a mixed pressure-displacement Finite Element Method. A complex Laplace transform scheme is used to study the time dependent variables. Several numerical examples are presented to validate and illustrate the efficiency of the proposed approach. PMID:26827028
A study of perfectly matched layers for joint multicomponent reverse-time migration
NASA Astrophysics Data System (ADS)
Du, Qi-Zhen; Sun, Rui-Yan; Qin, Tong; Zhu, Yi-Tong; Bi, Li-Fei
2010-06-01
Reverse-time migration in finite space requires effective boundary processing technology to eliminate the artificial truncation boundary effect in the migration result. On the basis of the elastic velocity-stress equations in vertical transversely isotropic media and the idea of the conventional split perfectly matched layer (PML), the PML wave equations in reverse-time migration are derived in this paper and then the high order staggered grid discrete schemes are subsequently given. Aiming at the “reflections” from the boundary to the computational domain, as well as the effect of seismic event’s abrupt changes at the two ends of the seismic array, the PML arrangement in reverse-time migration is given. The synthetic and real elastic, prestack, multi-component, reverse-time depth migration results demonstrate that this method has much better absorbing effects than other methods and the joint migration produces good imaging results.
Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing
2015-12-01
The complex frequency shifted perfectly matched layer (CFS-PML) can improve the absorbing performance of PML for nearly grazing incident waves. However, traditional PML and CFS-PML are based on first-order wave equations; thus, they are not suitable for second-order wave equation. In this paper, an implementation of CFS-PML for second-order wave equation is presented using auxiliary differential equations. This method is free of both convolution calculations and third-order temporal derivatives. As an unsplit CFS-PML, it can reduce the nearly grazing incidence. Numerical experiments show that it has better absorption than typical PML implementations based on second-order wave equation. PMID:26723366
Capacitive-loaded interstitial antennas for perfect matching and desirable SAR distributions.
Ahn, Hee-Ran; Lee, Kwyro
2006-02-01
New interstitial antennas are proposed. They basically consist of coaxial cable and two types of capacitive loads. One is tipped at the end of antennas, which helps almost perfect matching possible. The others are located in the middle and needed for better specific absorption rate (SAR) distribution. To distinguish them, one at the end is called the end-capacitive load (ECL) and the others in the middle the middle-capacitive loads (MCLs). Depending on the number of the MCLs, ZMIA (zero MCL interstitial antenna), OMIA (one MCL interstitial antenna) and two MCL interstitial antenna (TMIA) are named and a matching technique based on transmission line theory is suggested. To verify the technique, the three antennas immersed in muscle phantom are designed, fabricated, measured and compared. The measured reflection coefficients of ZMIA, OMIA, and TMIA are -28.4, -21.9, and -22.8 dB, respectively, one of which, -28.4 dB may be considered as the best among those reported. The compared results show that the measured ones are in good agreement with the calculated (predicted) ones. The three antennas are also measured for the SAR distributions. The measured results indicate that the TMIA has the best performance as expected and the region more than 43 degrees C is a rugby ball (major axis 6 cm and minor axis 2.9 cm) with only one TMIA, which confirms that they may be used for the treatment for big-sized and deep-seated tumor or cancer. PMID:16485757
Mennemann, Jan-Frederik Jüngel, Ansgar
2014-10-15
Discrete transparent boundary conditions (DTBC) and the Perfectly Matched Layers (PML) method for the realization of open boundary conditions in quantum device simulations are compared, based on the stationary and time-dependent Schrödinger equation. The comparison includes scattering state, wave packet, and transient scattering state simulations in one and two space dimensions. The Schrödinger equation is discretized by a second-order Crank–Nicolson method in case of DTBC. For the discretization with PML, symmetric second-, fourth-, and sixth-order spatial approximations as well as Crank–Nicolson and classical Runge–Kutta time-integration methods are employed. In two space dimensions, a ring-shaped quantum waveguide device is simulated in the stationary and transient regime. As an application, a simulation of the Aharonov–Bohm effect in this device is performed, showing the excitation of bound states localized in the ring region. The numerical experiments show that the results obtained from PML are comparable to those obtained using DTBC, while keeping the high numerical efficiency and flexibility as well as the ease of implementation of the former method. -- Highlights: •In-depth comparison between discrete transparent boundary conditions (DTBC) and PML. •First 2-D transient scattering state simulations using DTBC. •First 2-D transient scattering state simulations of the Aharonov–Bohm effect.
Fang, Sinan; Pan, Heping; Du, Ting; Konaté, Ahmed Amara; Deng, Chengxiang; Qin, Zhen; Guo, Bo; Peng, Ling; Ma, Huolin; Li, Gang; Zhou, Feng
2016-01-01
This study applied the finite-difference time-domain (FDTD) method to forward modeling of the low-frequency crosswell electromagnetic (EM) method. Specifically, we implemented impulse sources and convolutional perfectly matched layer (CPML). In the process to strengthen CPML, we observed that some dispersion was induced by the real stretch κ, together with an angular variation of the phase velocity of the transverse electric plane wave; the conclusion was that this dispersion was positively related to the real stretch and was little affected by grid interval. To suppress the dispersion in the CPML, we first derived the analytical solution for the radiation field of the magneto-dipole impulse source in the time domain. Then, a numerical simulation of CPML absorption with high-frequency pulses qualitatively amplified the dispersion laws through wave field snapshots. A numerical simulation using low-frequency pulses suggested an optimal parameter strategy for CPML from the established criteria. Based on its physical nature, the CPML method of simply warping space-time was predicted to be a promising approach to achieve ideal absorption, although it was still difficult to entirely remove the dispersion. PMID:27585538
A novel unsplit perfectly matched layer for the second-order acoustic wave equation.
Ma, Youneng; Yu, Jinhua; Wang, Yuanyuan
2014-08-01
When solving acoustic field equations by using numerical approximation technique, absorbing boundary conditions (ABCs) are widely used to truncate the simulation to a finite space. The perfectly matched layer (PML) technique has exhibited excellent absorbing efficiency as an ABC for the acoustic wave equation formulated as a first-order system. However, as the PML was originally designed for the first-order equation system, it cannot be applied to the second-order equation system directly. In this article, we aim to extend the unsplit PML to the second-order equation system. We developed an efficient unsplit implementation of PML for the second-order acoustic wave equation based on an auxiliary-differential-equation (ADE) scheme. The proposed method can benefit to the use of PML in simulations based on second-order equations. Compared with the existing PMLs, it has simpler implementation and requires less extra storage. Numerical results from finite-difference time-domain models are provided to illustrate the validity of the approach. PMID:24794509
Perfectly matched layers in a divergence preserving ADI scheme for electromagnetics
Kraus, C.; Adelmann, A.
2012-01-01
For numerical simulations of highly relativistic and transversely accelerated charged particles including radiation fast algorithms are needed. While the radiation in particle accelerators has wavelengths in the order of 100 {mu}m the computational domain has dimensions roughly five orders of magnitude larger resulting in very large mesh sizes. The particles are confined to a small area of this domain only. To resolve the smallest scales close to the particles subgrids are envisioned. For reasons of stability the alternating direction implicit (ADI) scheme by Smithe et al. [D.N. Smithe, J.R. Cary, J.A. Carlsson, Divergence preservation in the ADI algorithms for electromagnetics, J. Comput. Phys. 228 (2009) 7289-7299] for Maxwell equations has been adopted. At the boundary of the domain absorbing boundary conditions have to be employed to prevent reflection of the radiation. In this paper we show how the divergence preserving ADI scheme has to be formulated in perfectly matched layers (PML) and compare the performance in several scenarios.
Perfectly Matched Layer for Linearized Euler Equations in Open and Ducted Domains
NASA Technical Reports Server (NTRS)
Tam, Christopher K. W.; Auriault, Laurent; Cambuli, Francesco
1998-01-01
Recently, perfectly matched layer (PML) as an absorbing boundary condition has widespread applications. The idea was first introduced by Berenger for electromagnetic waves computations. In this paper, it is shown that the PML equations for the linearized Euler equations support unstable solutions when the mean flow has a component normal to the layer. To suppress such unstable solutions so as to render the PML concept useful for this class of problems, it is proposed that artificial selective damping terms be added to the discretized PML equations. It is demonstrated that with a proper choice of artificial mesh Reynolds number, the PML equations can be made stable. Numerical examples are provided to illustrate that the stabilized PML performs well as an absorbing boundary condition. In a ducted environment, the wave mode are dispersive. It will be shown that the group velocity and phase velocity of these modes can have opposite signs. This results in a confined environment, PML may not be suitable as an absorbing boundary condition.
Fang, Sinan; Pan, Heping; Du, Ting; Konaté, Ahmed Amara; Deng, Chengxiang; Qin, Zhen; Guo, Bo; Peng, Ling; Ma, Huolin; Li, Gang; Zhou, Feng
2016-01-01
This study applied the finite-difference time-domain (FDTD) method to forward modeling of the low-frequency crosswell electromagnetic (EM) method. Specifically, we implemented impulse sources and convolutional perfectly matched layer (CPML). In the process to strengthen CPML, we observed that some dispersion was induced by the real stretch κ, together with an angular variation of the phase velocity of the transverse electric plane wave; the conclusion was that this dispersion was positively related to the real stretch and was little affected by grid interval. To suppress the dispersion in the CPML, we first derived the analytical solution for the radiation field of the magneto-dipole impulse source in the time domain. Then, a numerical simulation of CPML absorption with high-frequency pulses qualitatively amplified the dispersion laws through wave field snapshots. A numerical simulation using low-frequency pulses suggested an optimal parameter strategy for CPML from the established criteria. Based on its physical nature, the CPML method of simply warping space-time was predicted to be a promising approach to achieve ideal absorption, although it was still difficult to entirely remove the dispersion. PMID:27585538
Tittl, Andreas; Harats, Moshe G; Walter, Ramon; Yin, Xinghui; Schäferling, Martin; Liu, Na; Rapaport, Ronen; Giessen, Harald
2014-10-28
Plasmonic devices with absorbance close to unity have emerged as essential building blocks for a multitude of technological applications ranging from trace gas detection to infrared imaging. A crucial requirement for such elements is the angle independence of the absorptive performance. In this work, we develop theoretically and verify experimentally a quantitative model for the angular behavior of plasmonic perfect absorber structures based on an optical impedance matching picture. To achieve this, we utilize a simple and elegant k-space measurement technique to record quantitative angle-resolved reflectance measurements on various perfect absorber structures. Particularly, this method allows quantitative reflectance measurements on samples where only small areas have been nanostructured, for example, by electron-beam lithography. Combining these results with extensive numerical modeling, we find that matching of both the real and imaginary parts of the optical impedance is crucial to obtain perfect absorption over a large angular range. Furthermore, we successfully apply our model to the angular dispersion of perfect absorber geometries with disordered plasmonic elements as a favorable alternative to current array-based designs. PMID:25251075
NASA Technical Reports Server (NTRS)
Garai, Anirban; Murman, Scott M.; Madavan, Nateri K.
2016-01-01
used involves modeling the pressure fluctuations as acoustic waves propagating in the far-field relative to a single noise-source inside the buffer region. This approach treats vorticity-induced pressure fluctuations the same as acoustic waves. Another popular approach, often referred to as the "sponge layer," attempts to dampen the flow perturbations by introducing artificial dissipation in the buffer region. Although the artificial dissipation removes all perturbations inside the sponge layer, incoming waves are still reflected from the interface boundary between the computational domain and the sponge layer. The effect of these refkections can be somewhat mitigated by appropriately selecting the artificial dissipation strength and the extent of the sponge layer. One of the most promising variants on the buffer region approach is the Perfectly Matched Layer (PML) technique. The PML technique mitigates spurious reflections from boundaries and interfaces by dampening the perturbation modes inside the buffer region such that their eigenfunctions remain unchanged. The technique was first developed by Berenger for application to problems involving electromagnetic wave propagation. It was later extended to the linearized Euler, Euler and Navier-Stokes equations by Hu and his coauthors. The PML technique ensures the no-reflection property for all waves, irrespective of incidence angle, wavelength, and propagation direction. Although the technique requires the solution of a set of auxiliary equations, the computational overhead is easily justified since it allows smaller domain sizes and can provide better accuracy, stability, and convergence of the numerical solution. In this paper, the PML technique is developed in the context of a high-order spectral-element Discontinuous Galerkin (DG) method. The technique is compared to other approaches to treating the in flow and out flow boundary, such as those based on using characteristic boundary conditions and sponge layers. The
Xie, Zhinan; Matzen, René; Cristini, Paul; Komatitsch, Dimitri; Martin, Roland
2016-07-01
A time-domain Legendre spectral-element method is described for full-wave simulation of ocean acoustics models, i.e., coupled fluid-solid problems in unbounded or semi-infinite domains, taking into account shear wave propagation in the ocean bottom. The technique can accommodate range-dependent and depth-dependent wave speed and density, as well as steep ocean floor topography. For truncation of the infinite domain, to efficiently absorb outgoing waves, a fluid-solid complex-frequency-shifted unsplit perfectly matched layer is introduced based on the complex coordinate stretching technique. The complex stretching is rigorously taken into account in the derivation of the fluid-solid matching condition inside the absorbing layer, which has never been done before in the time domain. Two implementations are designed: a convolutional formulation and an auxiliary differential equation formulation because the latter allows for implementation of high-order time schemes, leading to reduced numerical dispersion and dissipation, a topic of importance, in particular, in long-range ocean acoustics simulations. The method is validated for a two dimensional fluid-solid Pekeris waveguide and for a three dimensional seamount model, which shows that the technique is accurate and numerically long-time stable. Compared with widely used paraxial absorbing boundary conditions, the perfectly matched layer is significantly more efficient at absorbing both body waves and interface waves. PMID:27475142
Kong, Xiang-kun; Liu, Shao-Bin Bian, Bo-rui; Chen, Chen; Zhang, Hai-feng
2014-12-15
A novel, compact, and multichannel nonreciprocal absorber through a wave tunneling mechanism in epsilon-negative and matching metamaterials is theoretically proposed. Nonreciprocal absorption properties are acquired via the coupling together of evanescent and propagating waves in an asymmetric configuration, constituted of nonlinear plasma alternated with matching metamaterial. The absorption channel number can be adjusted by changing the periodic number. Due to the positive feedback between nonlinear permittivity of plasma and the inner electric field, bistable absorption and reflection are achieved. Moreover, compared with some truncated photonic crystal or multilayered designs proposed before, our design is more compact and independent of incident angle or polarization. This kind of multilayer structure offers additional opportunities to design novel omnidirectional electromagnetic wave absorbers.
Improved techniques for lower bounds for odd perfect numbers
NASA Astrophysics Data System (ADS)
Brent, R. P.; Cohen, G. L.; Riele, H. J. J. Te
1991-10-01
If N is an odd perfect number, and {q^k}\\vert\\vert N , q prime, k even, then it is almost immediate that N > {q^{2k}} . We prove here that, subject to certain conditions verifiable in polynomial time, in fact N > {q^{5k/2}} . Using this and related results, we are able to extend the computations in an earlier paper to show that N > {10^{300}} .
Improving the Nephrology Match: the Path Forward.
Hsu, Chi-yuan; Parker, Mark G; Ross, Michael J; Schmidt, Rebecca J; Harris, Raymond C
2015-11-01
The Fellowship Match process was designed to provide applicants and program directors with an opportunity to consider all their options before making decisions about post-residency training. In a Match, applicants can choose the programs that best suit their career goals, and program directors can consider all candidates before preparing a rank order list. The Match is a contract, requiring obligations of both programs and applicants to achieve success, ensure uniformity, and standardize participation. PMID:26341128
Matching X-ray beam and detector properties to protein crystals of different perfection
Nave, Colin
2014-01-01
An analysis is given of the effect of different beam and detector parameters on the sharpness of recorded diffraction features for macromolecular crystals of different quality. The crystal quality parameters include crystal strain, crystal or mosaic block size and mosaic block misorientation. Calculations are given for instrument parameters such as angular resolution of the detector, beam divergence and wavelength bandpass to be matched to the intrinsic diffraction properties from these crystals with the aim of obtaining the best possible data out of each crystal. Examples are given using typical crystal imperfections obtained from the literature for both room-temperature and cryo-cooled crystals. Possible implications for the choice of X-ray source, beamline design, detector specifications, instrument set-up and data processing are discussed, together with the limitations of the approach. PMID:24763643
Yu, Meina; Zhou, Xiaochen; Jiang, Jinghua; Yang, Huai; Yang, Deng-Ke
2016-05-11
Chiral nematic liquid crystals possess a self-assembled helical structure and exhibit unique selective reflection in visible and infrared light regions. Their optical properties can be electrically tuned. The tuning involves the unwinding and restoring of the helical structure. We carried out an experimental study on the mechanism of the restoration of the helical structure. We constructed chiral nematic liquid crystals with variable elastic constants by doping bent-dimers and studied their impact on the restoration. With matched twist and bend elastic constants, the helical structure can be restored dramatically fast from the field-induced homeotropic state. Furthermore, defects can be eliminated to produce a perfect planar state which exhibits high selective reflection. PMID:27116620
Improving The Perfect Storm: Overcoming Barriers To Climate Literacy
NASA Astrophysics Data System (ADS)
Tillinger, D.
2015-12-01
Students and scientists are trained to speak different languages. Climate science, and the geosciences more broadly, are strictly classroom topics, not subjects appropriate for casual conversation, social media, or creative projects. When students are aware of climate change through the mainstream media, it is nearly always in a political or technological context rather than a scientific one. However, given the opportunity, students are perfectly capable of not only understanding the science behind climate change, but communicating it to their peers. At the American Museum of Natural History, a group of underprivileged high school students visited Nature's Fury: The Science of Natural Disasters to learn about volcanoes, earthquakes, and climate change impacts. They were then able to write pitches and develop trailers for scientifically accurate, but still compelling, disaster movies. Arts in Parts, a creative outreach group formed as a response to Hurricane Sandy, facilitated a workshop in which younger children made mobiles from beach debris they collected while learning about the the threat of sea level rise locally and globally. Participants in an undergraduate natural disasters class wrote guides to understanding climate change that remained factual while showing great creativity and reflecting the personality of each student. Art, humor, and popular culture are the languages that society chooses to use; scientific literacy might benefit from their inclusion.
Improved robust point matching with label consistency
NASA Astrophysics Data System (ADS)
Bhagalia, Roshni; Miller, James V.; Roy, Arunabha
2010-03-01
Robust point matching (RPM) jointly estimates correspondences and non-rigid warps between unstructured point-clouds. RPM does not, however, utilize information of the topological structure or group memberships of the data it is matching. In numerous medical imaging applications, each extracted point can be assigned group membership attributes or labels based on segmentation, partitioning, or clustering operations. For example, points on the cortical surface of the brain can be grouped according to the four lobes. Estimated warps should enforce the topological structure of such point-sets, e.g. points belonging to the temporal lobe in the two point-sets should be mapped onto each other. We extend the RPM objective function to incorporate group membership labels by including a Label Entropy (LE) term. LE discourages mappings that transform points within a single group in one point-set onto points from multiple distinct groups in the other point-set. The resulting Labeled Point Matching (LPM) algorithm requires a very simple modification to the standard RPM update rules. We demonstrate the performance of LPM on coronary trees extracted from cardiac CT images. We partitioned the point sets into coronary sections without a priori anatomical context, yielding potentially disparate labelings (e.g. [1,2,3] --> [a,b,c,d]). LPM simultaneously estimated label correspondences, point correspondences, and a non-linear warp. Non-matching branches were treated wholly through the standard RPM outlier process akin to non-matching points. Results show LPM produces warps that are more physically meaningful than RPM alone. In particular, LPM mitigates unrealistic branch crossings and results in more robust non-rigid warp estimates.
Kakodkar, Rohit R.; Feser, Joseph P.
2015-09-07
We present a numerical approach to the solution of elastic phonon-interface and phonon-nanostructure scattering problems based on a frequency-domain decomposition of the atomistic equations of motion and the use of perfectly matched layer (PML) boundaries. Unlike molecular dynamic wavepacket analysis, the current approach provides the ability to simulate scattering from individual phonon modes, including wavevectors in highly dispersive regimes. Like the atomistic Green's function method, the technique reduces scattering problems to a system of linear algebraic equations via a sparse, tightly banded matrix regardless of dimensionality. However, the use of PML boundaries enables rapid absorption of scattered wave energies at the boundaries and provides a simple and inexpensive interpretation of the scattered phonon energy flux calculated from the energy dissipation rate in the PML. The accuracy of the method is demonstrated on connected monoatomic chains, for which an analytic solution is known. The parameters defining the PML are found to affect the performance and guidelines for selecting optimal parameters are given. The method is used to study the energy transmission coefficient for connected diatomic chains over all available wavevectors for both optical and longitudinal phonons; it is found that when there is discontinuity between sublattices, even connected chains of equivalent acoustic impedance have near-zero transmission coefficient for short wavelengths. The phonon scattering cross section of an embedded nanocylinder is calculated in 2D for a wide range of frequencies to demonstrate the extension of the method to high dimensions. The calculations match continuum theory for long-wavelength phonons and large cylinder radii, but otherwise show complex physics associated with discreteness of the lattice. Examples include Mie oscillations which terminate when incident phonon frequencies exceed the maximum available frequency in the embedded nanocylinder, and
NASA Astrophysics Data System (ADS)
Nguyen, K. L.; Treyssède, F.; Hazard, C.
2015-05-01
Among the numerous techniques of non-destructive evaluation, elastic guided waves are of particular interest to evaluate defects inside industrial and civil elongated structures owing to their ability to propagate over long distances. However for guiding structures buried in large solid media, waves can be strongly attenuated along the guide axis due to the energy radiation into the surrounding medium, usually considered as unbounded. Hence, searching the less attenuated modes becomes necessary in order to maximize the inspection distance. In the numerical modeling of embedded waveguides, the main difficulty is to account for the unbounded section. This paper presents a numerical approach combining a semi-analytical finite element method and a perfectly matched layer (PML) technique to compute the so-called trapped and leaky modes in three-dimensional embedded elastic waveguides of arbitrary cross-section. Two kinds of PML, namely the Cartesian PML and the radial PML, are considered. In order to understand the various spectral objects obtained by the method, the PML parameters effects upon the eigenvalue spectrum are highlighted through analytical studies and numerical experiments. Then, dispersion curves are computed for test cases taken from the literature in order to validate the approach.
Zampolli, Mario; Tesei, Alessandra; Jensen, Finn B; Malm, Nils; Blottman, John B
2007-09-01
A frequency-domain finite-element (FE) technique for computing the radiation and scattering from axially symmetric fluid-loaded structures subject to a nonsymmetric forcing field is presented. The Berenger perfectly matched layer (PML), applied directly at the fluid-structure interface, makes it possible to emulate the Sommerfeld radiation condition using FE meshes of minimal size. For those cases where the acoustic field is computed over a band of frequencies, the meshing process is simplified by the use of a wavelength-dependent rescaling of the PML coordinates. Quantitative geometry discretization guidelines are obtained from a priori estimates of small-scale structural wavelengths, which dominate the acoustic field at low to mid frequencies. One particularly useful feature of the PML is that it can be applied across the interface between different fluids. This makes it possible to use the present tool to solve problems where the radiating or scattering objects are located inside a layered fluid medium. The proposed technique is verified by comparison with analytical solutions and with validated numerical models. The solutions presented show close agreement for a set of test problems ranging from scattering to underwater propagation. PMID:17927408
Assi, Hisham; Cobbold, Richard S C
2016-04-01
Wave propagation in an infinite medium can be numerically simulated by surrounding a finite region by a perfectly matched layer (PML). When the medium is heterogeneous consisting of both solids and liquids, careful consideration is needed in specifying the properties of the PML especially because parts of it lie at the solid-fluid interface. While such a situation could arise in many important fields including marine seismology, where water is in contact with earth, and in biomedical ultrasound, where soft tissue is in contact with bone, no PML formulation exists to appropriately model such coupled problems. Here, a second-order time-domain PML formulation for fluid-solid heterogeneous media in two dimensions that satisfies the interface coupling boundary condition throughout the computational domain is presented. Numerical results are given to establish the applicability and accuracy of such a PML formulation in discrete settings without causing stability issues, spurious reflections, or any other problems. In particular, the effectiveness of the PML in absorbing all kinds of bulk waves, as well as surface and evanescent waves, is studied. PMID:27106301
Improving Student Laboratory Performance: How Much Practice Makes Perfect?
ERIC Educational Resources Information Center
Beasley, Warren
1985-01-01
Analyzes three approaches (physical, mental, combined practice) to improving freshman chemistry psychomotor laboratory skills. Although no significant differences were found between treatments, there were significant differences when each was compared to the control sections. Mental practice appears to offer an efficient methods for reinforcement…
A landmark matching algorithm using the improved generalised Hough transform
NASA Astrophysics Data System (ADS)
Chen, Binbin; Deng, Xingpu
2015-10-01
The paper addresses the issue on landmark matching of images from Geosynchronous Earth Orbit (GEO) satellites. In general, satellite imagery is matched against the base image, which is predefined. When the satellite imagery rotation occurs, the accuracy of many landmark matching algorithms deteriorates. To overcome this problem, generalised Hough transform (GHT) is employed for landmark matching. At first an improved GHT algorithm is proposed to enhance rotational invariance. Secondly a global coastline is processed to generate the test image as the satellite image and the base image. Then the test image is matched against the base image using the proposed algorithm. The matching results show that the proposed algorithm is rotation invariant and works well in landmark matching.
Improved artificial bee colony algorithm based gravity matching navigation method.
Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang
2014-01-01
Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position. PMID:25046019
NASA Astrophysics Data System (ADS)
Hayes, Charles E.; McClellan, James H.; Scott, Waymond R.; Kerr, Andrew J.
2016-05-01
This work introduces two advances in wide-band electromagnetic induction (EMI) processing: a novel adaptive matched filter (AMF) and matched subspace detection methods. Both advances make use of recent work with a subspace SVD approach to separating the signal, soil, and noise subspaces of the frequency measurements The proposed AMF provides a direct approach to removing the EMI self-response while improving the signal to noise ratio of the data. Unlike previous EMI adaptive downtrack filters, this new filter will not erroneously optimize the EMI soil response instead of the EMI target response because these two responses are projected into separate frequency subspaces. The EMI detection methods in this work elaborate on how the signal and noise subspaces in the frequency measurements are ideal for creating the matched subspace detection (MSD) and constant false alarm rate matched subspace detection (CFAR) metrics developed by Scharf The CFAR detection metric has been shown to be the uniformly most powerful invariant detector.
NASA Astrophysics Data System (ADS)
Duru, Kenneth; Kozdon, Jeremy E.; Kreiss, Gunilla
2015-12-01
In computations, it is now common to surround artificial boundaries of a computational domain with a perfectly matched layer (PML) of finite thickness in order to prevent artificially reflected waves from contaminating a numerical simulation. Unfortunately, the PML does not give us an indication about appropriate boundary conditions needed to close the edges of the PML, or how those boundary conditions should be enforced in a numerical setting. Terminating the PML with an inappropriate boundary condition or an unstable numerical boundary procedure can lead to exponential growth in the PML which will eventually destroy the accuracy of a numerical simulation everywhere. In this paper, we analyze the stability and the well-posedness of boundary conditions terminating the PML for the elastic wave equation in first order form. First, we consider a vertical modal PML truncating a two space dimensional computational domain in the horizontal direction. We freeze all coefficients and consider a left half-plane problem with linear boundary conditions terminating the PML. The normal mode analysis is used to study the stability and well-posedness of the resulting initial boundary value problem (IBVP). The result is that any linear well-posed boundary condition yielding an energy estimate for the elastic wave equation, without the PML, will also lead to a well-posed IBVP for the PML. Second, we extend the analysis to the PML corner region where both a horizontal and vertical PML are simultaneously active. The challenge lies in constructing accurate and stable numerical approximations for the PML and the boundary conditions. Third, we develop a high order accurate finite difference approximation of the PML subject to the boundary conditions. To enable accurate and stable numerical boundary treatments for the PML we construct continuous energy estimates in the Laplace space for a one space dimensional problem and two space dimensional PML corner problem. We use summation
NASA Astrophysics Data System (ADS)
Ping, Ping; Zhang, Yu; Xu, Yixian
2014-02-01
In order to conquer the spurious reflections from the truncated edges and maintain the stability in the long-time simulation of elastic wave propagation, several perfectly matched layer (PML) methods have been proposed in the first-order (e.g., velocity-stress equations) and the second-order (e.g., energy equation with displacement unknown only) formulations. The multiaxial perfectly matched layer (M-PML) holds the excellent stability for the long-time simulation of wave propagation, even though it is not perfectly matched in the discretized M-PML equation system. This absorbing boundary approach can offer an alternative way to solve the problem of the late-time instability, especially for anisotropic media, which is also suffered by the convolutional perfectly matched layer (C-PML) that is supposed to be competent to handle most stable problems. The M-PML termination implementation in the first-order formulations is well proposed. The common drawback of the implementation of the first-order M-PML formulations is that it necessitates fundamental reconstruction of the existing codes of the second-order spectral element method (SEM) or finite element method (FEM). Therefore, we propose a nonconvolutional second-order M-PML absorbing boundary condition approach for the wave propagation simulation in elastic media that has not yet been developed before. Two-dimensional numerical simulation validations demonstrate that the proposed second-order M-PML has good performances: 1) superior efficiency and stability of absorbing the spurious elastic wavefields, both the surface waves and body waves, reflected on the boundaries; 2) superior stability in the long-time simulation even in the isotropic medium with a high Poisson's ratio; 3) superior efficiency and stability in the long-time simulation for anisotropic media. This method hence makes the SEM and FEM in the second-order wave equation formulation more efficient and stable for the long-time simulation.
Cheng, Candong; Lee, Joon-Ho; Lim, Kim Hwa; Massoud, Hisham Z.; Liu, Qing Huo
2007-01-01
A 3-D quantum transport solver based on the spectral element method (SEM) and perfectly matched layer (PML) is introduced to solve the 3-D Schrödinger equation with a tensor effective mass. In this solver, the influence of the environment is replaced with the artificial PML open boundary extended beyond the contact regions of the device. These contact regions are treated as waveguides with known incident waves from waveguide mode solutions. As the transmitted wave function is treated as a total wave, there is no need to decompose it into waveguide modes, thus significantly simplifying the problem in comparison with conventional open boundary conditions. The spectral element method leads to an exponentially improving accuracy with the increase in the polynomial order and sampling points. The PML region can be designed such that less than −100 dB outgoing waves are reflected by this artificial material. The computational efficiency of the SEM solver is demonstrated by comparing the numerical and analytical results from waveguide and plane-wave examples, and its utility is illustrated by multiple-terminal devices and semiconductor nanotube devices. PMID:18037971
Improving Semi-Global Matching: Cost Aggregation and Confidence Measure
NASA Astrophysics Data System (ADS)
d'Angelo, Pablo
2016-06-01
Digital elevation models are one of the basic products that can be generated from remotely sensed imagery. The Semi Global Matching (SGM) algorithm is a robust and practical algorithm for dense image matching. The connection between SGM and Belief Propagation was recently developed, and based on that improvements such as correction of over-counting the data term, and a new confidence measure have been proposed. Later the MGM algorithm has been proposed, it aims at improving the regularization step of SGM, but has only been evaluated on the Middlebury stereo benchmark so far. This paper evaluates these proposed improvements on the ISPRS satellite stereo benchmark, using a Pleiades Triplet and a Cartosat-1 Stereo pair. The over-counting correction slightly improves matching density, at the expense of adding a few outliers. The MGM cost aggregation shows leads to a slight increase of accuracy.
Gun bore flaw image matching based on improved SIFT descriptor
NASA Astrophysics Data System (ADS)
Zeng, Luan; Xiong, Wei; Zhai, You
2013-01-01
In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor
Kozin, Elliott D.; Sethi, Rosh; Lehmann, Ashton; Remenschneider, Aaron K.; Golub, Justin S.; Reyes, Samuel A.; Emerick, Kevin; Lee, Daniel J.; Gray, Stacey T.
2015-01-01
Introduction “The Match” has become the accepted selection process for graduate medical education. Otomatch.com has provided an online forum for Otolaryngology-Head and Neck Surgery (OHNS) Match-related questions for over a decade. Herein, we aim to 1) delineate the types of posts on Otomatch to better understand the perspective of medical students applying for residency and 2) provide recommendations to potentially improve the Match process. Methods Discussion forum posts on Otomatch between December 2001 and April 2014 were reviewed. The title of each thread and total number of views were recorded for quantitative analysis. Each thread was organized into one of six major categories and one of eighteen subcategories, based on chronology within the application cycle and topic. National Resident Matching Program (NRMP) data were utilized for comparison. Results We identified 1,921 threads corresponding to over 2 million page views. Over 40% of threads related to questions about specific programs, and 27% were discussions about interviews. Views, a surrogate measure for popularity, reflected different trends. The majority of individuals viewed posts on interviews (42%), program specific questions (20%) and how to rank programs (11%). Increase in viewership tracked with a rise in applicant numbers based on NRMP data. Conclusions Our study provides an in depth analysis of a popular discussion forum for medical students interested in the OHNS Match. The most viewed posts are about interview dates and questions regarding specific programs. We provide suggestions to address unmet needs for medical students and potentially improve the Match process. PMID:25550223
Singing Video Games May Help Improve Pitch-Matching Accuracy
ERIC Educational Resources Information Center
Paney, Andrew S.
2015-01-01
The purpose of this study was to investigate the effect of singing video games on the pitch-matching skills of undergraduate students. Popular games like "Rock Band" and "Karaoke Revolutions" rate players' singing based on the correctness of the frequency of their sung response. Players are motivated to improve their…
Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo
2013-01-01
We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems. PMID:23888085
Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo
2013-02-15
We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems. PMID:23888085
NASA Astrophysics Data System (ADS)
Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo
2013-02-01
We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems.
Impedance matched joined drill pipe for improved acoustic transmission
Moss, William C.
2000-01-01
An impedance matched jointed drill pipe for improved acoustic transmission. A passive means and method that maximizes the amplitude and minimize the temporal dispersion of acoustic signals that are sent through a drill string, for use in a measurement while drilling telemetry system. The improvement in signal transmission is accomplished by replacing the standard joints in a drill string with joints constructed of a material that is impedance matched acoustically to the end of the drill pipe to which it is connected. Provides improvement in the measurement while drilling technique which can be utilized for well logging, directional drilling, and drilling dynamics, as well as gamma-ray spectroscopy while drilling post shot boreholes, such as utilized in drilling post shot boreholes.
NASA Astrophysics Data System (ADS)
Ueno, A.; Namekawa, Y.; Yamazaki, S.; Ohkoshi, K.; Koizumi, I.; Ikegami, K.; Takagi, A.; Oguri, H.
2013-02-01
In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) 2nd stage requirements of an H- ion beam current of 60mA within normalized emittances of 1.5πmmṡmrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of more than 50days, a cesiated RF-driven H- ion source using a internal-antenna developed at the Spallation Neutron Source (SNS) was developed. As similar as the SNS ion source, the 60kW pulsed 2MHz-RF and 200W CW 30MHz-RF systems are used in order to produce pulsed high-temperature 2MHz-RF plasma and CW low-temperature 30MHz-RF plasma. Each matching network for each system is composed of two vacuum variable condensers (VVCs). In order to supply pulsed 60kW-2MHz-RF power from the power supply (PS) on the ground level, a one-turn isolation transformer using FINEMET cores is installed between the PS and the J-PARC ion source. By comprehending the matching networks with the LTspice IV simulations and high- and low- power experiments and setting the parameters properly, the pulsed 2MHz-RF power up to 46 kW is successfully input to the hydrogen plasma without any misfire and with almost no reflected power.
NASA Astrophysics Data System (ADS)
Baccouche, Ryan; Tahar, Mabrouk Ben; Moreau, Solène
2016-09-01
A Perfectly Matched Layer (PML) for aeroacoustic problems using Galbrun's equation in the presence of an axial and a swirling steady mean flow is investigated in a cylindrical coordinates system. This equation is based on an Eulerian-Lagrangian description and leads to a wave equation written only in terms of the Lagrangian perturbation of the displacement. Galbrun's equation is solved by a mixed pressure-displacement Finite Element Method (FEM). To avoid instabilities in the presence of mean flow, a geometric transformation is presented. The validity and efficiency of the proposed PML formulation are established through comparisons with analytical, semi-analytical model based on Pridmore-Brown equation (extended to an axial and a swirling mean flow) and with multiple-scale models. The interest of the formulation is shown through an example of aeroacoustic radiation.
Accuracy of pitch matching significantly improved by live voice model.
Granot, Roni Y; Israel-Kolatt, Rona; Gilboa, Avi; Kolatt, Tsafrir
2013-05-01
Singing is, undoubtedly, the most fundamental expression of our musical capacity, yet an estimated 10-15% of Western population sings "out-of-tune (OOT)." Previous research in children and adults suggests, albeit inconsistently, that imitating a human voice can improve pitch matching. In the present study, we focus on the potentially beneficial effects of the human voice and especially the live human voice. Eighteen participants varying in their singing abilities were required to imitate in singing a set of nine ascending and descending intervals presented to them in five different randomized blocked conditions: live piano, recorded piano, live voice using optimal voice production, recorded voice using optimal voice production, and recorded voice using artificial forced voice production. Pitch and interval matching in singing were much more accurate when participants repeated sung intervals as compared with intervals played to them on the piano. The advantage of the vocal over the piano stimuli was robust and emerged clearly regardless of whether piano tones were played live and in full view or were presented via recording. Live vocal stimuli elicited higher accuracy than recorded vocal stimuli, especially when the recorded vocal stimuli were produced in a forced vocal production. Remarkably, even those who would be considered OOT singers on the basis of their performance when repeating piano tones were able to pitch match live vocal sounds, with deviations well within the range of what is considered accurate singing (M=46.0, standard deviation=39.2 cents). In fact, those participants who were most OOT gained the most from the live voice model. Results are discussed in light of the dual auditory-motor encoding of pitch analogous to that found in speech. PMID:23528675
Reading + Math = A Perfect Match
ERIC Educational Resources Information Center
Callan, Richard
2004-01-01
In this article, the author discusses how he incorporates children's literature into the exploration and investigation of various math topics. After doing some activities, he has found that integrating different mathematical topics after discussing books can help children make the connection to mathematics in their daily lives.
ERIC Educational Resources Information Center
Lassnigg, Lorenz
2008-01-01
This article discusses the implications of a framework to improve matching supply and demand in VET by a policy to improve quality by using anticipation and foresight approaches. Analysis of the Austrian anticipation system identified some basic aspects such as policy. The analysis focused on two issues: the observation and measurement of…
Improved Real-Time Scan Matching Using Corner Features
NASA Astrophysics Data System (ADS)
Mohamed, H. A.; Moussa, A. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, Abu B.
2016-06-01
The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute positioning measurements (e.g. GPS) are typically unavailable. Laser range finders are among the most widely used sensors that help the unmanned vehicles to localize themselves in indoor environments. Typically, automatic real-time matching of the successive scans is performed either explicitly or implicitly by any localization approach that utilizes laser range finders. Many accustomed approaches such as Iterative Closest Point (ICP), Iterative Matching Range Point (IMRP), Iterative Dual Correspondence (IDC), and Polar Scan Matching (PSM) handles the scan matching problem in an iterative fashion which significantly affects the time consumption. Furthermore, the solution convergence is not guaranteed especially in cases of sharp maneuvers or fast movement. This paper proposes an automated real-time scan matching algorithm where the matching process is initialized using the detected corners. This initialization step aims to increase the convergence probability and to limit the number of iterations needed to reach convergence. The corner detection is preceded by line extraction from the laser scans. To evaluate the probability of line availability in indoor environments, various data sets, offered by different research groups, have been tested and the mean numbers of extracted lines per scan for these data sets are ranging from 4.10 to 8.86 lines of more than 7 points. The set of all intersections between extracted lines are detected as corners regardless of the physical intersection of these line segments in the scan. To account for the uncertainties of the detected corners, the covariance of the corners is estimated using the extracted lines variances. The detected corners are used to estimate the transformation parameters between the
Improved Feature Matching for Mobile Devices with IMU.
Masiero, Andrea; Vettore, Antonio
2016-01-01
Thanks to the recent diffusion of low-cost high-resolution digital cameras and to the development of mostly automated procedures for image-based 3D reconstruction, the popularity of photogrammetry for environment surveys is constantly increasing in the last years. Automatic feature matching is an important step in order to successfully complete the photogrammetric 3D reconstruction: this step is the fundamental basis for the subsequent estimation of the geometry of the scene. This paper reconsiders the feature matching problem when dealing with smart mobile devices (e.g., when using the standard camera embedded in a smartphone as imaging sensor). More specifically, this paper aims at exploiting the information on camera movements provided by the inertial navigation system (INS) in order to make the feature matching step more robust and, possibly, computationally more efficient. First, a revised version of the affine scale-invariant feature transform (ASIFT) is considered: this version reduces the computational complexity of the original ASIFT, while still ensuring an increase of correct feature matches with respect to the SIFT. Furthermore, a new two-step procedure for the estimation of the essential matrix E (and the camera pose) is proposed in order to increase its estimation robustness and computational efficiency. PMID:27527186
Refractive index matching improves optical object detection in paper
NASA Astrophysics Data System (ADS)
Saarela, J. M. S.; Heikkinen, S. M.; Fabritius, T. E. J.; Haapala, A. T.; Myllylä, R. A.
2008-05-01
The demand for high-quality recycled pulp products has increased the need for an efficient deinking process. Assessing process efficiency via residual ink on test sheets has so far been limited to the sheet surface due to the poor transparency of paper. A refractive index matching method was studied to obtain a quantitative measure of particles within the volume of a paper sheet. In actual measurements a glass plate with etched lines from 8.5 µm to 281.1 µm wide was placed beneath the layers of cleared paper, and visible lines were counted with a microscope. Three different paper grades were tested with transparentizing agents. A diffusion theory-based regression model was used to find a correlation between transparency, paper grammage and paper thickness. These equations enable the determination of the size of an object detectable from a paper with a certain transparentizing agent or the parameters of a test sheet needed to detect objects of a known size. Anise oil was found to be the better of the two agents used, and they both had better transparentizing ability than air or water. The transparent paper grammage of the paper grades was determined for all the tested media. Paper's transparency was found to depend more on paper's thickness than grammage.
Using Local Matching to Improve Estimates of Program Impact: Evidence from Project STAR
ERIC Educational Resources Information Center
Jones, Nathan; Steiner, Peter; Cook, Tom
2011-01-01
In this study the authors test whether matching using intact local groups improves causal estimates over those produced using propensity score matching at the student level. Like the recent analysis of Wilde and Hollister (2007), they draw on data from Project STAR to estimate the effect of small class sizes on student achievement. They propose a…
Electrospun Vascular Grafts with Improved Compliance Matching to Native Vessels
Nezarati, Roya M.; Eifert, Michelle B.; Dempsey, David K.; Cosgriff-Hernandez, Elizabeth
2014-01-01
Coronary artery bypass grafting (CABG) is one of the most commonly performed major surgeries in the United States. Autologous vessels such as the saphenous vein are the current gold standard for treatment; however, synthetic vascular prostheses made of expanded poly(tetrafluoroethylene) (ePTFE) or poly(ethylene terephthalate) (PET) are used when autologous vessels are unavailable. These synthetic grafts have a high failure rate in small diameter (<4 mm) applications due to rapid re-occlusion via intimal hyperplasia. Current strategies to improve clinical performance are focused on preventing intimal hyperplasia by fabricating grafts with compliance and burst pressure similar to native vessels. To this end, we have developed an electrospun vascular graft from segmented polyurethanes with tunable properties by altering material chemistry and graft microarchitecture. Relationships between polyurethane tensile properties and biomechanical properties were elucidated to select polymers with desirable properties. Graft thickness, fiber tortuosity, and fiber fusions were modulated to provide additional tools for controlling graft properties. Using a combination of these strategies, a vascular graft with compliance and burst pressure exceeding the saphenous vein autograft was fabricated (compliance = 6.0 ± 0.6 %/mmHg × 10−4, burst pressure = 2260 ± 160 mmHg). This graft is hypothesized to reduce intimal hyperplasia associated with low compliance in synthetic grafts and improve long term clinical success. Additionally, the fundamental relationships between electrospun mesh microarchitecture and mechanical properties identified in this work can be utilized in various biomedical applications. PMID:24846218
Missile placement analysis based on improved SURF feature matching algorithm
NASA Astrophysics Data System (ADS)
Yang, Kaida; Zhao, Wenjie; Li, Dejun; Gong, Xiran; Sheng, Qian
2015-03-01
The precious battle damage assessment by use of video images to analysis missile placement is a new study area. The article proposed an improved speeded up robust features algorithm named restricted speeded up robust features, which combined the combat application of TV-command-guided missiles and the characteristics of video image. Its restrictions mainly reflected in two aspects, one is to restrict extraction area of feature point; the second is to restrict the number of feature points. The process of missile placement analysis based on video image was designed and a video splicing process and random sample consensus purification were achieved. The RSURF algorithm is proved that has good realtime performance on the basis of guarantee the accuracy.
An improved image matching algorithm based on SURF and Delaunay TIN
NASA Astrophysics Data System (ADS)
Cheng, Yuan-ming; Cheng, Peng-gen; Chen, Xiao-yong; Zheng, Shou-zhu
2015-12-01
Image matching is one of the key technologies in the image processing. In order to increase its efficiency and precision, a new method for image matching which based on the improved SURF and Delaunay-TIN is proposed in this paper. Based on the original SURF algorithm, three constraint conditions, color invariant model, Delaunay-TIN, triangle similarity function and photography invariant are added into the original SURF model. With the proposed algorithm, the image color information is effectively retained and the erroneous matching rate of features is largely reduced. The experimental results shows that this proposed method has the characteristics of higher matching speed, uniform distribution of feature points to be matched, and higher correct matching rate than the original algorithm does.
ERIC Educational Resources Information Center
DiConsiglio, John
2012-01-01
Alumni relations and stewardship officers have the makings of a strong partnership. Alumni relations and stewardship can be a natural fit--a perfect match even--according to Mary Jo Chiara of St. Joseph's College (SJC) in New York. Both strive to cultivate long-term relationships with constituents and build increasing levels of engagement and…
Improvements of AIMS D2DB matching for product patterns
NASA Astrophysics Data System (ADS)
Nishiguchi, Masaharu; Kanno, Koichi; Miyashita, Hiroyuki; Ohara, Kana; Son, Donghwan; Tolani, Vikram; Satake, Masaki
2015-07-01
AIMSTM is mainly used in photomask industry for verifying the print impact of mask defects on wafer CD in DUV lithography process. AIMS verification is typically used in D2D configuration, wherein two AIMS images, reference and defect, are captured and compared. Criticality of defects is then analyzed off these images using a number of criteria. As photomasks with aggressive OPC, sub-resolution assist features (SRAFs), and single-die are being routinely manufactured in production environment, it is required to improve cycle time through the AIMS step by saving time in searching for and capturing an adequate reference AIMS image. One solution is to use AIMS D2DB methodology which compares AIMS defect image with a reference image simulated from the corresponding mask design data. In general, such simulation needs calibration with the native images captured on the AIMS tool. In our previous paper we evaluated a calibration procedure directly using the defect AIMS image and compared the analysis results with a D2D capture using AIA (Aerial Image Analyzer) software product from Luminescent Technologies (now part of KLA-Tencor Corporation). The results showed that calibration using defect AIMS image does not influence AIMS judgment as long as the defect size is less than 100nm in case of typical basic patterns. When applying this methodology to product patterns, it was found that there were differences between reference AIMS image and simulation image. These differences influenced AIMS verification. Then new method to compensate would be needed. Our approach to compensate the difference between AIMS image and simulated image is examination with some factors likely to cause the difference.
Stephens, Thomas J; Sigler, Monya L; Herndon, James H; Dispensa, Lisa; Le Moigne, Anne
2016-01-01
Objective To assess the efficacy of Imedeen Time Perfection for improving the appearance and condition of photoaged skin in healthy women. Methods This randomized, double-blind, placebo-controlled clinical trial enrolled healthy women, 35–60 years of age, with Fitzpatrick I–III and Glogau II–III skin types and mild-to-moderate facial fine lines/wrinkles. The eligible subjects were randomized to receive two tablets daily of either Imedeen Time Perfection (Imedeen) or a matching placebo for 12 weeks. Efficacy assessments included investigator rating of 16 photoaging parameters (ie, global facial appearance and 15 individual facial parameters and the average of all parameters), instrumentation (ie, ultrasound dermal density, moisture level of the stratum corneum, transepidermal water loss, cutometry), and subjects’ self-assessment. Differences in the mean change from baseline to week 12 values on these outcomes were compared between Imedeen and placebo using analysis of variance or a paired t-test. Results Seventy-four subjects with primarily Fitzpatrick skin type III (78%–79%) and Glogau type III (53%–58%) completed the study (Imedeen: n=36; placebo: n=38). The mean difference in change from baseline to week 12 for global facial assessment significantly favored Imedeen over placebo (−0.52; P=0.0017). Additionally, the mean differences in the average of all facial photoaging parameters (−0.29), mottled hyperpigmentation (−0.25), tactile laxity (−0.24), dullness (−0.47), and tactile roughness (−0.62) significantly favored Imedeen over placebo (P≤0.05). Significantly greater increases in ultrasound dermal density (+11% vs +1%; P≤0.05) and stratum corneum moisturization (+30% vs +6%; P≤0.05) were also observed for Imedeen than for placebo. There were no significant differences on other instrumental outcomes. Conclusion The results of this study suggest that Imedeen Time Perfection can positively affect the appearance of photoaged skin
Similarity measures of full polarimetric SAR images fusion for improved SAR image matching
NASA Astrophysics Data System (ADS)
Ding, H.
2015-06-01
China's first airborne SAR mapping system (CASMSAR) developed by Chinese Academy of Surveying and Mapping can acquire high-resolution and full polarimetric (HH, HV, VH and VV) Synthetic aperture radar (SAR) data. It has the ability to acquire X-band full polarimetric SAR data at a resolution of 0.5m. However, the existence of speckles which is inherent in SAR imagery affects visual interpretation and image processing badly, and challenges the assumption that conjugate points appear similar to each other in matching processing. In addition, researches show that speckles are multiplicative speckles, and most similarity measures of SAR image matching are sensitive to them. Thus, matching outcomes of SAR images acquired by most similarity measures are not reliable and with bad accuracy. Meanwhile, every polarimetric SAR image has different backscattering information of objects from each other and four polarimetric SAR data contain most basic and a large amount of redundancy information to improve matching. Therefore, we introduced logarithmically transformation and a stereo matching similarity measure into airborne full polarimetric SAR imagery. Firstly, in order to transform the multiplicative speckles into additivity ones and weaken speckles' influence on similarity measure, logarithmically transformation have to be taken to all images. Secondly, to prevent performance degradation of similarity measure caused by speckles, measure must be free or insensitive of additivity speckles. Thus, we introduced a stereo matching similarity measure, called Normalized Cross-Correlation (NCC), into full polarimetric SAR image matching. Thirdly, to take advantage of multi-polarimetric data and preserve the best similarity measure value, four measure values calculated between left and right single polarimetric SAR images are fused as final measure value for matching. The method was tested for matching under CASMSAR data. The results showed that the method delivered an effective
Arbel, A. ); Sokolov, M. )
1994-04-01
The load matching characteristics of a thermosyphonic solar water heater can be improved by utilizing a thermostatic flow control (TFC). Simulation of the performance of a typical thermosyphonic domestic solar heater, with and without a TFC, was used to evaluate the yearly requirement of auxiliary energy to meet four different loads. The amount of yearly auxiliary energy required to fully match the load demands is used as a measure of the matching improvement. Results indicate that, for load temperatures of 40[degrees], 60[degrees], and 70[degrees] C, the thermostatic flow controller improves the system's (multi- or single-pass) performance, while the common single-pass system without the thermostatic flow controller is the best choice for a 50[degrees]C load temperature.
NASA Astrophysics Data System (ADS)
Tankersley, R. A.; Bourexis, P.; Kaser, J. S.
2011-12-01
Within the research and academic communities there is a growing interest in improving the communication skills of scientists, especially their ability to communicate the substance and importance of their research to general audiences. To address this need, we developed an intensive, two-day workshop [Presentation Boot Camp (PBC)] that focuses on presenting scientific concepts and research findings more effectively to both scientific/technical audiences and the general public. Through a series of interactive sessions, participants receive training in planning and preparing presentations that communicate messages more clearly and effectively and that have a lasting impact on the audience. Topics include: knowing and identifying the needs of the audience, highlighting big ideas and take-home messages, designing effective visuals, decoding complex concepts with diagrams, and displaying data in meaningful ways. PBC attendees also receive training in the use and application of the Presentation Skills Protocol (PSP) and associated rubric for evaluating the effectiveness of scientific presentations. The PSP was originally developed as part of a NSF Graduate Teaching Fellows in K-12 Education Program (GK-12) to assess and track the impact of the GK-12 experience on the communication skills of Graduate Teaching Fellows. The PSP focuses on eleven presentation skill sets, including organization, accuracy, relevance, message, language, equity, delivery, technology, use of time, questions, and presence. The associated rubric operationally defines each of the skill sets at three categorical levels of competence: (1) proficient, (2) developing, and (3) needs attention. The PSP may be used to (1) provide scientists with regular and consistent feedback on the quality and effectiveness of their classroom and research presentations and (2) design professional development activities and training programs that target specific presentation skills. However, our evaluation results indicate
Cui, Lingli; Wu, Na; Wang, Wenjing; Kang, Chenhui
2014-01-01
This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP) algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP) is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and reconstruction algorithm
Cui, Lingli; Wu, Na; Wang, Wenjing; Kang, Chenhui
2014-01-01
This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP) algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP) is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and reconstruction algorithm
Improved shape-signature and matching methods for model-based robotic vision
NASA Technical Reports Server (NTRS)
Schwartz, J. T.; Wolfson, H. J.
1987-01-01
Researchers describe new techniques for curve matching and model-based object recognition, which are based on the notion of shape-signature. The signature which researchers use is an approximation of pointwise curvature. Described here is curve matching algorithm which generalizes a previous algorithm which was developed using this signature, allowing improvement and generalization of a previous model-based object recognition scheme. The results and the experiments described relate to 2-D images. However, natural extensions to the 3-D case exist and are being developed.
NASA Astrophysics Data System (ADS)
Noordmans, Herke Jan; van den Biesen, Pieter; de Roode, Rowland; Verdaasdonk, Rudolf
2008-02-01
An interactive image matching program has been developed to help ophthalmologists in perceiving subtle differences between sequential images obtained during fluorescein angiography. In a pilot experiment, it appeared that the image matching program could effectively correct camera alignment errors. By offering simple tools like image overlay, blinking and image subtraction, differences between angiograms can be greatly enhanced and interpreted. It appeared that newly formed, leaking blood vessels could be detected at an earlier stage of the disease process using these tools. Treatment can be initiated right away, thereby preventing the patient from having additional visual loss. The matching program seems to improve the quality of fundus diagnostics but needs to be validated in future studies.
Developmental improvement and age-related decline in unfamiliar face matching.
Megreya, Ahmed M; Bindemann, Markus
2015-01-01
Age-related changes have been documented widely in studies of face recognition and eyewitness identification. However, it is not clear whether these changes arise from general developmental differences in memory or occur specifically during the perceptual processing of faces. We report two experiments to track such perceptual changes using a 1-in- 10 (experiment 1) and 1-in-1 (experiment 2) matching task for unfamiliar faces. Both experiments showed improvements in face matching during childhood and adult-like accuracy levels by adolescence. In addition, face-matching performance declined in adults of the age of 65 years. These findings indicate that developmental improvements and aging-related differences in face processing arise from changes in the perceptual encoding of faces. A clear face inversion effect was also present in all age groups. This indicates that those age-related changes in face matching reflect a quantitative effect, whereby typical face processes are engaged but do not operate at the best-possible level. These data suggest that part of the problem of eyewitness identification in children and elderly persons might reflect impairments in the perceptual processing of unfamiliar faces. PMID:26489213
E-beam column monitoring for improved CD SEM stability and tool matching
NASA Astrophysics Data System (ADS)
Hayes, Timothy S.; Henninger, Randall S.
2000-06-01
Tool matching is an important metric for in-line semiconductor metrology systems. The ability to obtain the same measurement results on two or more systems allows a semiconductor fabrication facility (fab) to deploy product in an efficient manner improving overall equipment efficiency (OEE). Many parameters on the critical dimension scanning electron microscopes (CDSEMs) can affect the long-term precision component to the tool-matching metric. One such class of parameters is related to the electron beam column stability. The alignment and condition of the gun and apertures, as well as astigmatism correction, have all been found to affect the overall measurements of the CDSEM. These effects are now becoming dominant factors in sub-3nm tool-matching criteria. This paper discusses the methodologies of column parameter monitoring and actions and controls for improving overall stability. Results have shown that column instabilities caused by contamination, gun fluctuations, component failures, detector efficiency, and external issues can be identified through parameter monitoring. The Applied Materials (AMAT) 7830 Series CDSEMs evaluated at IBM's Burlington, Vermont manufacturing facility have demonstrated 5 nm tool matching across 11 systems, which has resulted in non-dedicated product deployment and has significantly reduced cost of ownership.
NASA Astrophysics Data System (ADS)
Padma, S.; Sanjeevi, S.
2014-11-01
Mangrove ecosystem study is one of the main beneficiaries of the application of hyperspectral data and spectral matching techniques. Diversity and density of mangrove species leads to complexity of the ecosystem. Hence, species level mapping becomes difficult. Though hyperspectral images are appropriate for such a mapping, different mangrove species with closely matching spectra pose a challenge. This paper proposes a novel hyperspectral matching algorithm by integrating the stochastic Jeffries-Matusita measure (JM) and deterministic Spectral Angle Mapper (SAM) to accurately map most species of the mangrove ecosystem. The JM-SAM algorithm signifies the combination of an quantitative angle measure (SAM) and an qualitative distance measure (JM). The spectral capabilities of both the measures are orthogonally projected using tangent and sine functions to result in the combined algorithm. The developed JM-SAM algorithm is implemented to discriminate the mangrove species and the landcover classes of Pichavaram and Muthupet mangrove forests of southern India using the Hyperion datasets. The developed algorithm is extended in a supervised framework for improved classification of the Hyperion image. The reference spectra of the mangrove species and other cover types are extracted from the Hyperion image. From the values of relative spectral discriminatory probability and relative discriminatory entropy value, it can be inferred that hybrid JM-SAM matching measure results in improved discriminability than the individual SAM and JM algorithms. This performance is reflected in the classification results where the JM-SAM (TAN) and JM-SAM (SIN) matching algorithms yielded an improved accuracy of (86.25%,85%) and (88.10%, 86.96) for both the study sites.
Improving the efficiency of the genetic code by varying the codon length--the perfect genetic code.
Doig, A J
1997-10-01
The function of DNA is to specify protein sequences. The four-base "alphabet" used in nucleic acids is translated to the 20 base alphabet of proteins (plus a stop signal) via the genetic code. The code is neither overlapping nor punctuated, but has mRNA sequences read in successive triplet codons until reaching a stop codon. The true genetic code uses three bases for every amino acid. The efficiency of the genetic code can be significantly increased if the requirement for a fixed codon length is dropped so that the more common amino acids have shorter codon lengths and rare amino acids have longer codon lengths. More efficient codes can be derived using the Shannon-Fano and Huffman coding algorithms. The compression achieved using a Huffman code cannot be improved upon. I have used these algorithms to derive efficient codes for representing protein sequences using both two and four bases. The length of DNA required to specify the complete set of protein sequences could be significantly shorter if transcription used a variable codon length. The restriction to a fixed codon length of three bases means that it takes 42% more DNA than the minimum necessary, and the genetic code is 70% efficient. One can think of many reasons why this maximally efficient code has not evolved: there is very little redundancy so almost any mutation causes an amino acid change. Many mutations will be potentially lethal frame-shift mutations, if the mutation leads to a change in codon length. It would be more difficult for the machinery of transcription to cope with a variable codon length. Nevertheless, in the strict and narrow sense of coding for protein sequences using the minimum length of DNA possible, the Huffman code derived here is perfect. PMID:9344740
Video object tracking using improved chamfer matching and condensation particle filter
NASA Astrophysics Data System (ADS)
Wu, Tao; Ding, Xiaoqing; Wang, Shengjin; Wang, Kongqiao
2008-02-01
Object tracking is an essential problem in the field of video and image processing. Although tracking algorithms working on gray video are convenient in actual applications, they are more difficult to be developed than those using color features, since less information is taken into account. Few researches have been dedicated to tracking object using edge information. In this paper, we proposed a novel video tracking algorithm based on edge information for gray videos. This method adopts the combination of a condensation particle filter and an improved chamfer matching. The improved chamfer matching is rotation invariant and capable of estimating the shift between an observed image patch and a template by an orientation distance transform. A modified discriminative likelihood measurement method that focuses on the difference is adopted. These values are normalized and used as the weights of particles which predict and track the object. Experiment results show that our modifications to chamfer matching improve its performance in video tracking problem. And the algorithm is stable, robust, and can effectively handle rotation distortion. Further work can be done on updating the template to adapt to significant viewpoint and scale changes of the appearance of the object during the tracking process.
Dependability Improvement for PPM Compressed Data by Using Compression Pattern Matching
NASA Astrophysics Data System (ADS)
Kitakami, Masato; Okura, Toshihiro
Data compression is popularly applied to computer systems and communication systems in order to reduce storage size and communication time, respectively. Since large data are used frequently, string matching for such data takes a long time. If the data are compressed, the time gets much longer because decompression is necessary. Long string matching time makes computer virus scan time longer and gives serious influence to the security of data. From this, CPM (Compression Pattern Matching) methods for several compression methods have been proposed. This paper proposes CPM method for PPM which achieves fast virus scan and improves dependability of the compressed data, where PPM is based on a Markov model, uses a context information, and achieves a better compression ratio than BW transform and Ziv-Lempel coding. The proposed method encodes the context information, which is generated in the compression process, and appends the encoded data at the beginning of the compressed data as a header. The proposed method uses only the header information. Computer simulation says that augmentation of the compression ratio is less than 5 percent if the order of the PPM is less than 5 and the source file size is more than 1M bytes, where order is the maximum length of the context used in PPM compression. String matching time is independent of the source file size and is very short, less than 0.3 micro seconds in the PC used for the simulation.
The design of an improved matched filter in DSSS-GMSK system
NASA Astrophysics Data System (ADS)
Wei-tong, Mao; Lin-hua', Zheng; Liang-jun, Xiang; Tan, Wang
2016-02-01
This paper introduces the principle of DSSS-GMSK system, analyses the superiority of GMSK modulation over MSK modulation. Accord that the method of de-spread before demodulation can effectively improve the capability of the system with spread spectrum gain, this paper researches an improved method with matched filter to de-spread and demodulate the DSSS signals. The local PN code is modulated with GMSK modulation before being correlated with received signal, then we can get the synchronous PN code, de-spread and demodulate the signal. MATLAB simulation shows that this method is more efficient than the method of demodulation before despread in low SNR environment.
An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method
NASA Astrophysics Data System (ADS)
Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John
2015-04-01
Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.
Improved Electrical Load Match In California By Combining Solar Thermal Power Plants with Wind Farms
Vick, B. D.; Clark, R. N.; Mehos, M.
2008-01-01
will be during mid-day. Adding six hours of solar thermal storage improved the utility load match significantly in the evening and reliability was also improved. Storage improves reliability because electrical production can remain at a high level even when there are lulls in the wind or clouds decrease the solar energy striking the parabolic trough mirrors. The solar energy from Mojave Desert and wind energy in the major wind farm areas are not a good match to utility load during the winter in California, but if the number of wind farms were increased east of San Diego, then the utility renewable energy match would be improved (this is because the wind energy is highest during the winter in this area). Currently in California, wind electrical generation only contributes 1.8% of total electricity and solar electrical generation only contributes 0.2%. Combining wind farms and solar thermal power plants with storage would allow a large percentage of the electrical load in California to be met by wind and solar energy due to a better match with utility load than by either renewable resource separately.
NASA Astrophysics Data System (ADS)
Yu, Fei; Hui, Mei; Han, Wei; Wang, Peng; Dong, Li-quan; Zhao, Yue-jin
2010-12-01
Image block matching is one of the motion estimation methods for video inter-frame coding and digital image stabilization. The methods used for matching and searching will greatly affect the accuracy and speed of block matching. The block matching method based on the oblique vectors is suggested in this paper where matching parameters contain both horizontal and vertical vectors in the image blocks at the same time. Improved matching information can be obtained after making correlative calculations in the oblique direction. A novel search method of matching block based on the idea of simulated annealing is presented in this paper to improve the searching speed, accuracy and robustness in the fast operation of the block-matching motion estimation. The simulated annealing algorithm can easily escape from the trap of local minima effectively. With the two methods the block matching can be used for motion estimation at the real-time image processing system and high estimation accuracy can be achieved. An image stabilization system based on DSP (Digital Signal Processing) system is developed to verify this algorithm. Results show that both the matching accuracy and the search speed are improved with the methods presented.
Neuroplasticity and MRI: A perfect match.
Hamaide, Julie; De Groof, Geert; Van der Linden, Annemie
2016-05-01
Numerous studies have illustrated the benefits of physical workout and cognitive exercise on brain function and structure and, more importantly, on decelerating cognitive decline in old age and promoting functional rehabilitation following injury. Despite these behavioral observations, the exact mechanisms underlying these neuroplastic phenomena remain obscure. This gap illustrates the need for carefully designed in-depth studies using valid models and translational tools which allow to uncover the observed events up to the molecular level. We promote the use of in vivo magnetic resonance imaging (MRI) because it is a powerful translational imaging technique able to extract functional, structural, and biochemical information from the entire brain. Advanced processing techniques allow performing voxel-based analyses which are capable of detecting novel loci implicated in specific neuroplastic events beyond traditional regions-of-interest analyses. In addition, its non-invasive character sets it as currently the best global imaging tool for performing dynamic longitudinal studies on the same living subject, allowing thus exploring the effects of experience, training, treatment etc. in parallel to additional measures such as age, cognitive performance scores, hormone levels, and many others. The aim of this review is (i) to introduce how different animal models contributed to extend the knowledge on neuroplasticity in both health and disease, over different life stages and upon various experiences, and (ii) to illustrate how specific MRI techniques can be applied successfully to inform on the fundamental mechanisms underlying experience-dependent or activity-induced neuroplasticity including cognitive processes. PMID:26260430
NASA Astrophysics Data System (ADS)
Luppescu, Gregory C.; Dawson, Alexander J.; Michaels, Jennifer E.
2016-02-01
Although bulk waves have served as the industry standard in nondestructive evaluation for many years, guided waves (Lamb waves in plates) have become the focus of many current research efforts because they are able to interrogate larger areas of a structure in less time. Despite this advantage, guided waves also have characteristics that obfuscate data interpretation. The first property of guided waves that complicates analysis is their dispersive nature: their wave speed is a function of frequency. The second is that they are multimodal: they propagate as multiple symmetric and antisymmetric modes. Using pulse-compression techniques and a priori calculations of theoretical dispersion curves, the dispersive matched filter attempts to take advantage of these otherwise undesirable characteristics by maximizing the autocorrelation for only one mode, ideally increasing both the signal-to-noise ratio and time-resolution of ultrasonic guided wave measurements. In this research, the responses from broadband chirp excitations are recorded from a sparse transducer array after propagation through an aluminum plate containing no damage and simulated damage. Dispersive matched filtering is applied to the measurements and localization images are generated using the delay-and-sum method. Imaging results are compared to those obtained with narrowband tone burst excitations in terms of their ability to detect and localize the different scatterers. Results show that the dispersive matched filter notably improves the quality of the localization images.
NASA Astrophysics Data System (ADS)
Yamada, Keisuke; Matsuhisa, Hiroshi; Utsuno, Hideo
2014-01-01
This paper describes new methods that improve the efficiency of a piezoelectric element attached to a beam based on mechanical impedance matching. Piezoelectric elements are often used to suppress bending vibration. They are also used as sensors or energy-harvesting sources. In such cases, the piezoelectric element is usually bonded onto the host structure by an adhesive bond. The efficiency of the piezoelectric element depends on the bonding location. When the efficiency is insufficient despite a good location, the size or number of piezoelectric elements is increased. However, the efficiency of the piezoelectric element is usually insufficient even if these methods are applied. In order to enhance the efficiency of the piezoelectric elements without using active methods, this paper proposes a mechanical impedance matching method that uses spacers or tuning for the size of the piezoelectric element. Because the attached piezoelectric element and host structure in this region behave as springs in parallel to the bending deformation, the stored strain energy in the piezoelectric element is maximized under the condition that their spring constants match. The proposed methods were theoretically investigated with consideration for the effects of the bonding layer, spacers, and host structure. The optimum conditions for the proposed methods were theoretically formulated, and the effectiveness of the proposed methods and theoretical analysis was verified through simulations and experiments.
Accuracy Improvement by the Least Squares Image Matching Evaluated on the CARTOSAT-1
NASA Astrophysics Data System (ADS)
Afsharnia, H.; Azizi, A.; Arefi, H.
2015-12-01
Generating accurate elevation data from satellite images is a prerequisite step for applications that involve disaster forecasting and management using GIS platforms. In this respect, the high resolution satellite optical sensors may be regarded as one of the prime and valuable sources for generating accurate and updated elevation information. However, one of the main drawbacks of conventional approaches for automatic elevation generation from these satellite optical data using image matching techniques is the lack of flexibility in the image matching functional models to take dynamically into account the geometric and radiometric dissimilarities between the homologue stereo image points. The classical least squares image matching (LSM) method, on the other hand, is quite flexible in incorporating the geometric and radiometric variations of image pairs into its functional model. The main objective of this paper is to evaluate and compare the potential of the LSM technique for generating disparity maps from high resolution satellite images to achieve sub pixel precision. To evaluate the rate of success of the LSM, the size of the y-disparities between the homologous points is taken as the precision criteria. The evaluation is performed on the Cartosat-1 stereo along track images over a highly mountainous terrain. The precision improvement is judged based on the standard deviation and the scatter pattern of the y-disparity data. The analysis of the results indicate that, the LSM has achieved the matching precision of about 0.18 pixels which is clearly superior to the manual pointing that yielded the precision of 0.37 pixels.
NASA Astrophysics Data System (ADS)
Robertson, Scott Patrick
To improve relatively poor outcomes for locally-advanced lung cancer patients, many current efforts are dedicated to minimizing uncertainties in radiotherapy. This enables the isotoxic delivery of escalated tumor doses, leading to better local tumor control. The current dissertation specifically addresses inter-fractional uncertainties resulting from patient setup variability. An automatic block-matching registration (BMR) algorithm is implemented and evaluated for the purpose of directly localizing advanced-stage lung tumors during image-guided radiation therapy. In this algorithm, small image sub-volumes, termed "blocks", are automatically identified on the tumor surface in an initial planning computed tomography (CT) image. Each block is independently and automatically registered to daily images acquired immediately prior to each treatment fraction. To improve the accuracy and robustness of BMR, this algorithm incorporates multi-resolution pyramid registration, regularization with a median filter, and a new multiple-candidate-registrations technique. The result of block-matching is a sparse displacement vector field that models local tissue deformations near the tumor surface. The distribution of displacement vectors is aggregated to obtain the final tumor registration, corresponding to the treatment couch shift for patient setup correction. Compared to existing rigid and deformable registration algorithms, the final BMR algorithm significantly improves the overlap between target volumes from the planning CT and registered daily images. Furthermore, BMR results in the smallest treatment margins for the given study population. However, despite these improvements, large residual target localization errors were noted, indicating that purely rigid couch shifts cannot correct for all sources of inter-fractional variability. Further reductions in treatment uncertainties may require the combination of high-quality target localization and adaptive radiotherapy.
Stamoulis, Catherine; Betensky, Rebecca A
2016-01-01
We aim to improve the performance of the previously proposed signal decomposition matched filtering (SDMF) method [26] for the detection of copy-number variations (CNV) in the human genome. Through simulations, we show that the modified SDMF is robust even at high noise levels and outperforms the original SDMF method, which indirectly depends on CNV frequency. Simulations are also used to develop a systematic approach for selecting relevant parameter thresholds in order to optimize sensitivity, specificity and computational efficiency. We apply the modified method to array CGH data from normal samples in the cancer genome atlas (TCGA) and compare detected CNVs to those estimated using circular binary segmentation (CBS) [19], a hidden Markov model (HMM)-based approach [11] and a subset of CNVs in the Database of Genomic Variants. We show that a substantial number of previously identified CNVs are detected by the optimized SDMF, which also outperforms the other two methods. PMID:27295643
An Improved Algorithm of Congruent Matching Cells (CMC) Method for Firearm Evidence Identifications
Tong, Mingsi; Song, John; Chu, Wei
2015-01-01
The Congruent Matching Cells (CMC) method was invented at the National Institute of Standards and Technology (NIST) for firearm evidence identifications. The CMC method divides the measured image of a surface area, such as a breech face impression from a fired cartridge case, into small correlation cells and uses four identification parameters to identify correlated cell pairs originating from the same firearm. The CMC method was validated by identification tests using both 3D topography images and optical images captured from breech face impressions of 40 cartridge cases fired from a pistol with 10 consecutively manufactured slides. In this paper, we discuss the processing of the cell correlations and propose an improved algorithm of the CMC method which takes advantage of the cell correlations at a common initial phase angle and combines the forward and backward correlations to improve the identification capability. The improved algorithm is tested by 780 pairwise correlations using the same optical images and 3D topography images as the initial validation. PMID:26958441
Zhou, Ru; Zhong, Dexing; Han, Jiuqiang
2013-01-01
The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT) descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1) the similar patterns of parallel ridges; and (2) high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD) to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM), is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA) achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements. PMID:23467056
Zhou, Ru; Zhong, Dexing; Han, Jiuqiang
2013-01-01
The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT) descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1) the similar patterns of parallel ridges; and (2) high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD) to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM), is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA) achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements. PMID:23467056
An Improved Algorithm of Congruent Matching Cells (CMC) Method for Firearm Evidence Identifications.
Tong, Mingsi; Song, John; Chu, Wei
2015-01-01
The Congruent Matching Cells (CMC) method was invented at the National Institute of Standards and Technology (NIST) for firearm evidence identifications. The CMC method divides the measured image of a surface area, such as a breech face impression from a fired cartridge case, into small correlation cells and uses four identification parameters to identify correlated cell pairs originating from the same firearm. The CMC method was validated by identification tests using both 3D topography images and optical images captured from breech face impressions of 40 cartridge cases fired from a pistol with 10 consecutively manufactured slides. In this paper, we discuss the processing of the cell correlations and propose an improved algorithm of the CMC method which takes advantage of the cell correlations at a common initial phase angle and combines the forward and backward correlations to improve the identification capability. The improved algorithm is tested by 780 pairwise correlations using the same optical images and 3D topography images as the initial validation. PMID:26958441
An improvement in IMRT QA results and beam matching in linacs using statistical process control.
Gagneur, Justin D; Ezzell, Gary A
2014-01-01
The purpose of this study is to apply the principles of statistical process control (SPC) in the context of patient specific intensity-modulated radiation therapy (IMRT) QA to set clinic-specific action limits and evaluate the impact of changes to the multileaf collimator (MLC) calibrations on IMRT QA results. Ten months of IMRT QA data with 247 patient QAs collected on three beam-matched linacs were retrospectively analyzed with a focus on the gamma pass rate (GPR) and the average ratio between the measured and planned doses. Initial control charts and action limits were calculated. Based on this data, changes were made to the leaf gap parameter for the MLCs to improve the consistency between linacs. This leaf gap parameter is tested monthly using a MLC sweep test. A follow-up dataset with 424 unique QAs were used to evaluate the impact of the leaf gap parameter change. The initial data average GPR was 98.6% with an SPC action limit of 93.7%. The average ratio of doses was 1.003, with an upper action limit of 1.017 and a lower action limit of 0.989. The sweep test results for the linacs were -1.8%, 0%, and +1.2% from nominal. After the adjustment of the leaf gap parameter, all sweep test results were within 0.4% of nominal. Subsequently, the average GPR was 99.4% with an SPC action limit of 97.3%. The average ratio of doses was 0.997 with an upper action limit of 1.011 and a lower action limit of 0.981. Applying the principles of SPC to IMRT QA allowed small differences between closely matched linacs to be identified and reduced. Ongoing analysis will monitor the process and be used to refine the clinical action limits for IMRT QA. PMID:25207579
Catarino, S O; Minas, G; Miranda, J M
2016-07-01
This paper reports the use of acoustic waves for promoting and improving streaming in tridimensional polymethylmethacrylate (PMMA) cuvettes of 15mm width×14mm height×2.5mm thickness. The acoustic waves are generated by a 28μm thick poly(vinylidene fluoride) - PVDF - piezoelectric transducer in its β phase, actuated at its resonance frequency: 40MHz. The acoustic transmission properties of two materials - SU-8 and polydimethylsiloxane (PDMS) - were numerically compared. It was concluded that PDMS inhibits, while SU-8 allows, the transmission of the acoustic waves to the propagation medium. Therefore, by simulating the acoustic transmission properties of different materials, it is possible to preview the acoustic behavior in the fluidic system, which allows the optimization of the best layout design, saving costs and time. This work also presents a comparison between numerical and experimental results of acoustic streaming obtained with that β-PVDF transducer in the movement and in the formation of fluid recirculation in tridimensional closed domains. Differences between the numerical and experimental results are credited to the high sensitivity of acoustic streaming to the experimental conditions and to limitations of the numerical method. The reported study contributes for the improvement of simulation models that can be extremely useful for predicting the acoustic effects of new materials in fluidic devices, as well as for optimizing the transducers and matching layers positioning in a fluidic structure. PMID:27044029
ERIC Educational Resources Information Center
Vixie Sandy, Mary
2013-01-01
This study investigated a problem facing policy makers, education leaders, and external providers of service that support or facilitate school-based change designed to improve teaching and learning: How to match school needs with providers' services in ways that maximize school improvement. A growing number of organizations provide service to…
Oran, Betül; Cao, Kai; Saliba, Rima M.; Rezvani, Katayoun; de Lima, Marcos; Ahmed, Sairah; Hosing, Chitra M.; Popat, Uday R.; Carmazzi, Yudith; Kebriaei, Partow; Nieto, Yago; Rondon, Gabriela; Willis, Dana; Shah, Nina; Parmar, Simrit; Olson, Amanda; Moore, Brandt; Marin, David; Mehta, Rohtesh; Fernández-Viña, Marcelo; Champlin, Richard E.; Shpall, Elizabeth J.
2015-01-01
Cord blood transplant requires less stringent human leukocyte antigen matching than unrelated donors. In 133 patients with hematologic malignancies who engrafted after double cord blood transplantation with a dominant unit, we studied the effect of high resolution testing at 4 loci (-A, -B, -C, -DRB1) for its impact on 2-year transplant-related mortality. Ten percent of the dominant cord blood units were matched at 7–8/8 alleles using HLA-A, -B, -C, and -DRB1; 25% were matched at 6/8, 40% at 5/8, and 25% at 4/8 or less allele. High resolution typing at 4 loci showed that there was no 2-year transplant-related mortality in 7–8/8 matched patients. Patients with 5–6/8 matched dominant cord blood units had 2-year transplant-related mortality of 39% while patients with 4/8 or less matched units had 60%. Multivariate regression analyses confirmed the independent effect of high resolution typing on the outcome when adjusted for age, diagnosis, CD34+ cell dose infused, graft manipulation and cord to cord matching. The worst prognostic group included patients aged over 32 years with 4/8 or less matched cord blood units compared with patients who were either younger than 32 years old independent of allele-level matching, or aged over 32 years but with 5–6/8 matched cord blood units (Hazard Ratio 2.2; 95% confidence interval: 1.3–3.7; P<0.001). Patients with 7–8/8 matched units remained the group with the best prognosis. Our data suggest that high resolution typing at 4 loci and selecting cord blood units matched at at least 5/8 alleles may reduce transplant-related mortality after double cord blood transplantation. PMID:26250579
Jeffries Matusita based mixed-measure for improved spectral matching in hyperspectral image analysis
NASA Astrophysics Data System (ADS)
Padma, S.; Sanjeevi, S.
2014-10-01
This paper proposes a novel hyperspectral matching technique by integrating the Jeffries-Matusita measure (JM) and the Spectral Angle Mapper (SAM) algorithm. The deterministic Spectral Angle Mapper and stochastic Jeffries-Matusita measure are orthogonally projected using the sine and tangent functions to increase their spectral ability. The developed JM-SAM algorithm is implemented in effectively discriminating the landcover classes and cover types in the hyperspectral images acquired by PROBA/CHRIS and EO-1 Hyperion sensors. The reference spectra for different land-cover classes were derived from each of these images. The performance of the proposed measure is compared with the performance of the individual SAM and JM approaches. From the values of the relative spectral discriminatory probability (RSDPB) and relative discriminatory entropy value (RSDE), it is inferred that the hybrid JM-SAM approach results in a high spectral discriminability than the SAM and JM measures. Besides, the use of the improved JM-SAM algorithm for supervised classification of the images results in 92.9% and 91.47% accuracy compared to 73.13%, 79.41%, and 85.69% of minimum-distance, SAM and JM measures. It is also inferred that the increased spectral discriminability of JM-SAM measure is contributed by the JM distance. Further, it is seen that the proposed JM-SAM measure is compatible with varying spectral resolutions of PROBA/CHRIS (62 bands) and Hyperion (242 bands).
Goeke, R.; Farnsworth, A.V.; Neumann, C.C.; Sweatt, W.C.; Warren, M.E.; Weed, J.W.
1996-06-01
This report discusses a novel fabrication process to produce nearly perfect optics. The process utilizes vacuum deposition techniques to optimally modify polished optical substrate surfaces. The surface figure, i.e. contour of a polished optical element, is improved by differentially filling in the low spots on the surface using flux from a physical vapor deposition source through an appropriate mask. The process is expected to enable the manufacture of diffraction-limited optical systems for the UV, extreme UV, and soft X-ray spectral regions, which would have great impact on photolithography and astronomy. This same technique may also reduce the fabrication cost of visible region optics with aspheric surfaces.
Bush, K; Holcombe, C; Kapp, D; Buyyounouski, M; Hancock, S; Xing, L; Atwood, T; King, M
2014-06-15
Purpose: Radiation-therapy dose-escalation beyond 80Gy may improve tumor control rates for patients with localized prostate cancer. Since toxicity remains a concern, treatment planners must achieve dose-escalation while still adhering to dose-constraints for surrounding structures. Patientmatching is a machine-learning technique that identifies prior patients that dosimetrically match DVH parameters of target volumes and critical structures prior to actual treatment planning. We evaluated the feasibility of patient-matching in (1)identifying candidates for safe dose-escalation; and (2)improving DVH parameters for critical structures in actual dose-escalated plans. Methods: We analyzed DVH parameters from 319 historical treatment plans to determine which plans could achieve dose-escalation (8640cGy) without exceeding Zelefsky dose-constraints (rectal and bladder V47Gy<53%, and V75.6Gy<30%, max-point dose to rectum of 8550cGy, max dose to PTV< 9504cGy). We then estimated the percentage of cases that could achieve safe dose-escalation using software that enables patient matching (QuickMatch, Siris Medical, Mountain View, CA). We then replanned a case that had violated DVH constraints with DVH parameters from patient matching, in order to determine whether this previously unacceptable plan could be made eligible with this automated technique. Results: Patient-matching improved the percentage of patients eligible for dose-escalation from 40% to 63% (p=4.7e-4, t-test). Using a commercial optimizer augmented with patient-matching, we demonstrated a case where patient-matching improved the toxicity-profile such that dose-escalation would have been possible; this plan was rapidly achieved using patientmatching software. In this patient, all lower-dose constraints were met with both the denovo and patient-matching plan. In the patient-matching plan, maximum dose to the rectum was 8385cGy, while the denovo plan failed to meet the maximum rectal constraint at 8571c
Improving cross-resolution face matching using ensemble-based co-transfer learning.
Bhatt, Himanshu S; Singh, Richa; Vatsa, Mayank; Ratha, Nalini K
2014-12-01
Face recognition algorithms are generally trained for matching high-resolution images and they perform well for similar resolution test data. However, the performance of such systems degrades when a low-resolution face image captured in unconstrained settings, such as videos from cameras in a surveillance scenario, are matched with high-resolution gallery images. The primary challenge, here, is to extract discriminating features from limited biometric content in low-resolution images and match it to information rich high-resolution face images. The problem of cross-resolution face matching is further alleviated when there is limited labeled positive data for training face recognition algorithms. In this paper, the problem of cross-resolution face matching is addressed where low-resolution images are matched with high-resolution gallery. A co-transfer learning framework is proposed, which is a cross-pollination of transfer learning and co-training paradigms and is applied for cross-resolution face matching. The transfer learning component transfers the knowledge that is learnt while matching high-resolution face images during training to match low-resolution probe images with high-resolution gallery during testing. On the other hand, co-training component facilitates this transfer of knowledge by assigning pseudolabels to unlabeled probe instances in the target domain. Amalgamation of these two paradigms in the proposed ensemble framework enhances the performance of cross-resolution face recognition. Experiments on multiple face databases show the efficacy of the proposed algorithm and compare with some existing algorithms and a commercial system. In addition, several high profile real-world cases have been used to demonstrate the usefulness of the proposed approach in addressing the tough challenges. PMID:25314702
An improved earthquake catalogue in the Marmara Sea region, Turkey, using massive template matching
NASA Astrophysics Data System (ADS)
Matrullo, Emanuela; Lengliné, Olivier; Schmittbuhl, Jean; Karabulut, Hayrullah; Bouchon, Michel
2016-04-01
After the 1999 Izmit earthquake, the Main Marmara Fault (MMF) represents a 150 km unruptured segment of the North Anatolian Fault located below the Marmara Sea. One of the principal issue for seismic hazard assessment in the region is to know if the MMF is totally or partially locked and where the nucleation of the major forthcoming event is going to take place. The area is actually one of the best-instrumented fault systems in Europe. Since year 2007, various seismic networks both broadband, short period and OBS stations were deployed in order to monitor continuously the seismicity along the MMF and the related fault systems. A recent analysis of the seismicity recorded during the 2007-2012 period has provided new insights on the recent evolution of this important regional seismic gap. This analysis was based on events detected with STA/LTA procedure and manually picked P and S wave arrivals times (Schmittbuhl et al., 2015). In order to extend the level of details and to fully take advantage of the dense seismic network we improved the seismic catalog using an automatic earthquake detection technique based on a template matching approach. This approach uses known earthquake seismic signals in order to detect newer events similar to the tested one from waveform cross-correlation. To set-up the methodology and verify the accuracy and the robustness of the results, we initially focused in the eastern part of the Marmara Sea (Cinarcik basin) and compared new detection with those manually identified. Through the massive analysis of cross-correlation based on the template scanning of the continuous recordings, we construct a refined catalog of earthquakes for the Marmara Sea in 2007-2014 period. Our improved earthquake catalog will provide an effective tool to improve the catalog completeness, to monitor and study the fine details of the time-space distribution of events, to characterize the repeating earthquake source processes and to understand the mechanical state of
ERIC Educational Resources Information Center
Scott, Paul
2007-01-01
In "Just Perfect: Part 1," the author defined a perfect number N to be one for which the sum of the divisors d (1 less than or equal to d less than N) is N. He gave the first few perfect numbers, starting with those known by the early Greeks. In this article, the author provides an extended list of perfect numbers, with some comments about their…
Visual Bearing-Only Simultaneous Localization and Mapping with Improved Feature Matching
NASA Astrophysics Data System (ADS)
Strasdat, Hauke; Stachniss, Cyrill; Bennewitz, Maren; Burgard, Wolfram
In this this paper, we present a solution to the simultaneous localization and mapping (SLAM) problem for a robot equipped with a single perspective camera. We track extracted features over multiple frames to estimate the depth information. To represent the joint posterior about the trajectory of the robot and a map of the environment, we apply a Rao-Blackwellized particle filter. We present a novel method to match features using a cost function that takes into account differences between the feature descriptor vectors as well as spatial information. To find an optimal matching between observed features, we apply a global optimization algorithm. Experimental results obtained with a real robot show that our approach is robust and tolerant to noise in the odometry information of the robot. Furthermore, we present experiments that demonstrate the superior performance of our feature matching technique compared to other approaches.
ERIC Educational Resources Information Center
Arsalidou, Marie; Pascual-Leone, Juan; Johnson, Janice
2010-01-01
The theory of constructive operators was used as a framework to design two versions of a paradigm (color matching task, CMT) in which items are parametrically ordered in difficulty, and differ only contextually. Items in CMT-Balloon are facilitating, whereas items in CMT-Clown contain misleading cues. Participants of ages 7-14 years and adults (N…
Improved electrical load match in California by combining solar thermal power plants with wind farms
Technology Transfer Automated Retrieval System (TEKTRAN)
The ability of wind and solar electrical energy generation to match the current utility electrical load in California was analyzed. We compared the renewable electrical generation and the utility load in California using actual hourly wind farm data at two different locations and predicted hourly p...
Zhu, Minchen; Wang, Weizhi; Liu, Binghan; Huang, Jingshan
2013-01-01
Video panoramic image stitching is extremely time-consuming among other challenges. We present a new algorithm: (i) Improved, self-adaptive selection of Harris corners. The successful stitching relies heavily on the accuracy of corner selection. We fragment each image into numerous regions and select corners within each region according to the normalized variance of region grayscales. Such a selection is self-adaptive and guarantees that corners are distributed proportional to region texture information. The possible clustering of corners is also avoided. (ii) Multiple-constraint corner matching. The traditional Random Sample Consensus (RANSAC) algorithm is inefficient, especially when handling a large number of images with similar features. We filter out many inappropriate corners according to their position information, and then generate candidate matching pairs based on grayscales of adjacent regions around corners. Finally we apply multiple constraints on every two pairs to remove incorrectly matched pairs. By a significantly reduced number of iterations needed in RANSAC, the stitching can be performed in a much more efficient manner. Experiments demonstrate that (i) our corner matching is four times faster than normalized cross-correlation function (NCC) rough match in RANSAC and (ii) generated panoramas feature a smooth transition in overlapping image areas and satisfy real-time human visual requirements. PMID:24324675
Matrix-Matching as an Improvement Strategy for the Detection of Pesticide Residues.
Giacinti, Géraldine; Raynaud, Christine; Capblancq, Sophie; Simon, Valérie
2016-05-01
More than 90% of the pesticides residues in apples are located in the peel. We developed a gas chromatography/ion trap tandem mass spectrometry method for investigating all detectable residues in the peel of 3 apple varieties. Sample preparation is based on the use of the Quick Easy Cheap Effective Rugged and Safe method on the whole fruit, the flesh, and the peel. Pesticide residues were quantified with solvent-matched and matrix-matched standards, by spiking apple sample extracts. Matrix effects dependent on the type of extract (fruit, flesh, or peel) and the apple variety were detected. The best data processing methods involved normalizing matrix effect rates by matrix-matched internal/external calibration. Boscalid, captan, chlorpyrifos, fludioxonil, and pyraclostrobin were the most frequently detected pesticides. However, their concentrations in the whole fruit were below European maximum residue levels. Despite negative matrix effects, the residues in peel were detected at concentrations up to 10 times higher than those in whole fruits. Consequently, other pesticide residues present at concentrations below the limit of quantification in the whole fruit were detected in the peel. PMID:27095394
NASA Technical Reports Server (NTRS)
Ray, J. R.; Smalley, L. L.
1982-01-01
The description of the spin given here is classical in that it is intrinsic but not quantized. The approach in this matter is similar to, for example, the work of Bailey and Israel (1973, 1975, 1979), where the fluid particles, which have intrinsic spin, may be galaxies or clusters of galaxies. The elementary particles of these objects and the 'ferromagnetic alignment' of their quantum spins are not resorted to in order to describe a fluid with spin. Physically this means that the equation of motion for the spin tensor is a modified Fermi-Walker transport equation (Misner et al., 1973), arising as a direct result of the inclusion of spin as an intrinsic variable in the thermodynamic description of the internal energy. The variables in this description are classical variables throughout and are not microscopic fields. An improved perfect-fluid energy-momentum tensor that includes spin and torsion is presented. Use is made of a Lagrangian variational principle based on the tetrad formalism of Halbwach (1960) and the method od constraints of Ray (1972).
ERIC Educational Resources Information Center
Landphair, Juliette
2007-01-01
What exactly is perfect? Students describe perfection as a combination of characteristics valued by their peer culture: intelligence, thin and fit physical appearance, social poise. As students chug through their daily lives--morning classes, organization meetings, club sports practice or the gym, dinner, another class, more meetings, library,…
NASA Astrophysics Data System (ADS)
Wang, Tianyang; Wüchner, Roland; Sicklinger, Stefan; Bletzinger, Kai-Uwe
2016-05-01
This paper investigates data mapping between non-matching meshes and geometries in fluid-structure interaction. Mapping algorithms for surface meshes including nearest element interpolation, the standard mortar method and the dual mortar method are studied and comparatively assessed. The inconsistency problem of mortar methods at curved edges of fluid-structure-interfaces is solved by a newly developed enforcing consistency approach, which is robust enough to handle even the case that fluid boundary facets are totally not in contact with structure boundary elements due to high fluid refinement. Besides, tests with representative geometries show that the mortar methods are suitable for conservative mapping but it is better to use the nearest element interpolation in a direct way, and moreover, the dual mortar method can give slight oscillations. This work also develops a co-rotating mapping algorithm for 1D beam elements. Its novelty lies in the ability of handling large displacements and rotations.
Köster, Andreas; Spura, Thomas; Rutkai, Gábor; Kessler, Jan; Wiebeler, Hendrik; Vrabec, Jadran; Kühne, Thomas D
2016-07-15
The accuracy of water models derived from ab initio molecular dynamics simulations by means on an improved force-matching scheme is assessed for various thermodynamic, transport, and structural properties. It is found that although the resulting force-matched water models are typically less accurate than fully empirical force fields in predicting thermodynamic properties, they are nevertheless much more accurate than generally appreciated in reproducing the structure of liquid water and in fact superseding most of the commonly used empirical water models. This development demonstrates the feasibility to routinely parametrize computationally efficient yet predictive potential energy functions based on accurate ab initio molecular dynamics simulations for a large variety of different systems. © 2016 Wiley Periodicals, Inc. PMID:27232117
A dynamic system matching technique for improving the accuracy of MEMS gyroscopes
Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.
2014-12-10
A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT
A dynamic system matching technique for improving the accuracy of MEMS gyroscopes
NASA Astrophysics Data System (ADS)
Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.
2014-12-01
A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT
Huang, Xiaoqiang; Xue, Jing; Lin, Min; Zhu, Yushan
2016-01-01
Active site preorganization helps native enzymes electrostatically stabilize the transition state better than the ground state for their primary substrates and achieve significant rate enhancement. In this report, we hypothesize that a complex active site model for active site preorganization modeling should help to create preorganized active site design and afford higher starting activities towards target reactions. Our matching algorithm ProdaMatch was improved by invoking effective pruning strategies and the native active sites for ten scaffolds in a benchmark test set were reproduced. The root-mean squared deviations between the matched transition states and those in the crystal structures were < 1.0 Å for the ten scaffolds, and the repacking calculation results showed that 91% of the hydrogen bonds within the active sites are recovered, indicating that the active sites can be preorganized based on the predicted positions of transition states. The application of the complex active site model for de novo enzyme design was evaluated by scaffold selection using a classic catalytic triad motif for the hydrolysis of p-nitrophenyl acetate. Eighty scaffolds were identified from a scaffold library with 1,491 proteins and four scaffolds were native esterase. Furthermore, enzyme design for complicated substrates was investigated for the hydrolysis of cephalexin using scaffold selection based on two different catalytic motifs. Only three scaffolds were identified from the scaffold library by virtue of the classic catalytic triad-based motif. In contrast, 40 scaffolds were identified using a more flexible, but still preorganized catalytic motif, where one scaffold corresponded to the α-amino acid ester hydrolase that catalyzes the hydrolysis and synthesis of cephalexin. Thus, the complex active site modeling approach for de novo enzyme design with the aid of the improved ProdaMatch program is a promising approach for the creation of active sites with high catalytic
Huang, Xiaoqiang; Xue, Jing; Lin, Min; Zhu, Yushan
2016-01-01
Active site preorganization helps native enzymes electrostatically stabilize the transition state better than the ground state for their primary substrates and achieve significant rate enhancement. In this report, we hypothesize that a complex active site model for active site preorganization modeling should help to create preorganized active site design and afford higher starting activities towards target reactions. Our matching algorithm ProdaMatch was improved by invoking effective pruning strategies and the native active sites for ten scaffolds in a benchmark test set were reproduced. The root-mean squared deviations between the matched transition states and those in the crystal structures were < 1.0 Å for the ten scaffolds, and the repacking calculation results showed that 91% of the hydrogen bonds within the active sites are recovered, indicating that the active sites can be preorganized based on the predicted positions of transition states. The application of the complex active site model for de novo enzyme design was evaluated by scaffold selection using a classic catalytic triad motif for the hydrolysis of p-nitrophenyl acetate. Eighty scaffolds were identified from a scaffold library with 1,491 proteins and four scaffolds were native esterase. Furthermore, enzyme design for complicated substrates was investigated for the hydrolysis of cephalexin using scaffold selection based on two different catalytic motifs. Only three scaffolds were identified from the scaffold library by virtue of the classic catalytic triad-based motif. In contrast, 40 scaffolds were identified using a more flexible, but still preorganized catalytic motif, where one scaffold corresponded to the α-amino acid ester hydrolase that catalyzes the hydrolysis and synthesis of cephalexin. Thus, the complex active site modeling approach for de novo enzyme design with the aid of the improved ProdaMatch program is a promising approach for the creation of active sites with high catalytic
On Improving Analytical Models of Cosmic Reionization for Matching Numerical Simulations
Kaurov, Alexander A.
2016-01-01
The methods for studying the epoch of cosmic reionization vary from full radiative transfer simulations to purely analytical models. While numerical approaches are computationally expensive and are not suitable for generating many mock catalogs, analytical methods are based on assumptions and approximations. We explore the interconnection between both methods. First, we ask how the analytical framework of excursion set formalism can be used for statistical analysis of numerical simulations and visual representation of the morphology of ionization fronts. Second, we explore the methods of training the analytical model on a given numerical simulation. We present a new code which emerged from this study. Its main application is to match the analytical model with a numerical simulation. Then, it allows one to generate mock reionization catalogs with volumes exceeding the original simulation quickly and computationally inexpensively, meanwhile reproducing large scale statistical properties. These mock catalogs are particularly useful for CMB polarization and 21cm experiments, where large volumes are required to simulate the observed signal.
The tip of the iceberg: improving the quality of rank order lists for the match.
Baker, Keith
2013-09-01
Many factors limit the ability of resident selection committees to reliably determine which medical student applicants will be top performers in their internship and residency programs. Resident selection committees expend significant time and effort to read applications and then interview and score applicants, all with the goal of creating a rank order list (ROL) for the National Residency Matching Program. Although much of the information used in this process is outside the control of the selection committee, one factor they can control is how they use committee member scores to create the ROL. ROLs are typically generated using the average score assigned by committee members. With this approach, a single harsh faculty member can strongly influence the rank order of applicants if he or she scores only some of the applicants.The author of this commentary discusses the challenges inherent in the creation of ROLs and examines a new approach, described by Ross and Moore in this issue, that can eliminate the problem of biased scoring. ROLs created using this new ROSS-MOORE (Recruitment Outcomes Simulation System-Moore Optimized Ordinal Rank Estimator) approach will better represent the rank ordering of each faculty member of the selection committee. However, ROLs will remain poorly predictive of future performance in internship and residency programs until evaluative data supplied by medical schools are more accurate in predicting which students will become excellent physicians. PMID:23887012
NASA Astrophysics Data System (ADS)
Kokic, Philip; Jin, Huidong; Crimp, Steven
2013-08-01
Statistical downscaling methods are commonly used to address the scale mismatch between coarse resolution Global Climate Model output and the regional or local scales required for climate change impact assessments. The effectiveness of a downscaling method can be measured against four broad criteria: consistency with the existing baseline data in terms of means, trends and distributional characteristics; consistency with the broader scale climate data used to generate the projections; the degree of transparency and repeatability; and the plausibility of results produced. Many existing downscaling methods fail to fulfil all of these criteria. In this paper we examine a block bootstrap simulation technique combined with a quantile prediction and matching method for simulating future daily climate data. By utilising this method the distributional properties of the projected data will be influenced by the distribution of the observed data, the trends in predictors derived from the Global Climate Models and the relationship of these predictors to the observed data. Using observed data from several climate stations in Vanuatu and Fiji and out-of-sample validation techniques, we show that the method is successful at projecting various climate characteristics including the variability and auto-correlation of daily temperature and rainfall, the correlations between these variables and between spatial locations. This paper also illustrates how this novel method can produce more effective point scale projections and a more credible alternative to other approaches in the Pacific region.
Charrondiere, U Ruth; Rittenschober, Doris; Nowak, Verena; Stadlmayr, Barbara; Wijesinha-Bettoni, Ramani; Haytowitz, David
2016-02-15
Food composition data play a key role in many sectors and the availability of quality data is critically important. Since 1984, the International Network of Food Data Systems (INFOODS) has been working towards improving food composition data quality and availability, including the development and updating of standards, guidelines and tools for food composition. FAO/INFOODS has recently published three comprehensive guidelines to improve and harmonise the compilation of data: (1) Guidelines for Food Matching, (2) Guidelines for Checking Food Composition Data prior to Publication of a User Table/Database, and (3) Guidelines for Converting Units, Denominators and Expressions. This article describes their content and development processes. Their adoption, along with additional ones planned for the future by FAO/INFOODS, should further improve the quality of published food composition data, which in turn can lead to more accurate nutrient intake estimates and more precise food labels, as well as better-targeted programs and policies. PMID:26433290
Optical object detection in paper improved by refractive index matching and mechanical treatment
NASA Astrophysics Data System (ADS)
Saarela, J.; Heikkinen, S.; Fabritius, T.; Myllylä, R.
2008-06-01
Two different paper grades were tested with a clearing agent to measure how much mechanical smoothening can improve transparency inside paper. The paper grades were newsprint and supercalendered paper. The paper furnishes of both papers were alike, but the supercalendered paper was mechanically smoothened. Anise oil was used as the clearing agent, but similar measurements were also done with air and water. Black lines 8.5 μm to 281.1 μm wide were placed behind layers of cleared paper and transparency was measured with a microscope. When anise oil was the clearing agent, supercalendering improved transparent paper grammage from 139 g/m2 to 164 g/m2. With water the improvement was from 40 g/m2 to 51 g/m2. With air the improvement was not determinable. As a conclusion, it is recommended that paper is smoothened if it needs to be studied optically. Optical coherence tomography, for example, would benefit from this treatment.
ERIC Educational Resources Information Center
Scott, Paul
2007-01-01
This article is about a very small subset of the positive integers. The positive integer N is said to be "perfect" if it is the sum of all its divisors, including 1, but less that N itself. For example, N = 6 is perfect, because the (relevant) divisors are 1, 2 and 3, and 6 = 1 + 2 + 3. On the other hand, N = 12 has divisors 1, 2, 3, 4 and 6, but…
Even Perfect Numbers: (Update)2.
ERIC Educational Resources Information Center
Bezuszka, Stanley J.; Kenney, Margaret J.
1997-01-01
Presents an assignment given to students to produce a report on perfect numbers and their properties. Summarizes the history of perfect numbers and their features. Recommends spreadsheet, theoretical, and programming activities on perfect numbers. (ASK)
2015-01-01
Core–shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III arsenides, however selection of inappropriate, lattice-mismatched shell materials have frequently caused undesired strain accumulation, defect formation, and modifications of the electronic band structure. Here, we demonstrate the realization of closely lattice-matched radial InGaAs–InAlAs core–shell NWs tunable over large compositional ranges [x(Ga)∼y(Al) = 0.2–0.65] via completely catalyst-free selective-area molecular beam epitaxy. On the basis of high-resolution X-ray reciprocal space maps the strain in the NW core is found to be insignificant (ε < 0.1%), which is further reflected by the absence of strain-induced spectral shifts in luminescence spectra and nearly unmodified band structure. Remarkably, the lattice-matched InAlAs shell strongly enhances the optical efficiency by up to 2 orders of magnitude, where the efficiency enhancement scales directly with increasing band offset as both Ga- and Al-contents increase. Ultimately, we fabricated vertical InGaAs−InAlAs NW/Si photovoltaic cells and show that the enhanced internal quantum efficiency is directly translated to an energy conversion efficiency that is ∼3–4 times larger as compared to an unpassivated cell. These results highlight the promising performance of lattice-matched III–V core–shell NW heterostructures with significant impact on future development of related nanophotonic and electronic devices. PMID:25922974
Improving pediatric cardiac surgical care in developing countries: matching resources to needs.
Dearani, Joseph A; Neirotti, Rodolfo; Kohnke, Emily J; Sinha, Kingshuk K; Cabalka, Allison K; Barnes, Roxann D; Jacobs, Jeffrey P; Stellin, Giovanni; Tchervenkov, Christo I; Cushing, John C
2010-01-01
This article reviews a systematic approach to the design and support of pediatric cardiac surgery programs in the developing world with the guidance and strategies of Children's HeartLink, an experienced non-government organization for more than 40 years. An algorithm with criteria for the selection of a partner site is outlined. A comprehensive education strategy from the physician to the allied health care provider is the mainstay for successful program development. In a partner program, the road to successful advancement and change depends on many factors, such as government support, hospital administration support, medical staff leadership, and a committed and motivated faculty with requisite skills, incentives, and resources. In addition to these factors, it is essential that the development effort includes considerations of environment (eg, governmental support, regulatory environment, and social structure) and health system (elements related to affordability, access, and awareness of care) that impact success. Partner programs should be willing to initiate a clinical database with the intent to analyze and critique their results to optimize quality assurance and improve outcomes. PMID:20307859
NASA Astrophysics Data System (ADS)
Goldman, Nir
In this work, we show that force matching can be used to determine accurate density functional tight binding (DFTB) models for reactive materials under extreme conditions. Determination of chemical reactivity in high-pressure experiments is an unsolved problem that can span timescales orders of magnitude longer that what can be achieved with standard quantum simulation approaches, such as Kohn-Sham Density Functional Theory. DFTB holds promise as a semi-empirical quantum simulation method that yields a high degree of computational efficiency while potentially retaining the accuracy of these higher order methods. Here, we show that force matching can be used to determine accurate repulsive energies for DFTB for chemical reactivity in condensed phases. Our new models yield improved predictions for physical properties of molten liquid carbon, as well as small molecule production in phenolic polymer combustion. Our approach is general and can be implemented as a way to extend quantum simulations to several orders of magnitude longer timescales than previously possible, allowing for direct comparison with experiments.
Wang, Wenyi; Wu, Renbiao
2013-01-01
DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy algorithms, have been recognized as a kind of novel DOA estimation algorithm. However, the success of these algorithms is limited by the RIP (Restricted Isometry Property) condition or the mutual coherence of measurement matrix. In the DOA estimation problem, the columns of measurement matrix are steering vectors corresponding to different DOAs. Thus, it violates the mutual coherence condition. The situation gets worse when there are two sources from two adjacent DOAs. In this paper, an algorithm based on OMP (Orthogonal Matching Pursuit), called ILS-OMP (Iterative Local Searching-Orthogonal Matching Pursuit), is proposed to improve DOA resolution by Iterative Local Searching. Firstly, the conventional OMP algorithm is used to obtain initial estimated DOAs. Then, in each iteration, a local searching process for every estimated DOA is utilized to find a new DOA in a given DOA set to further decrease the residual. Additionally, the estimated DOAs are updated by substituting the initial DOA with the new one. The simulation results demonstrate the advantages of the proposed algorithm. PMID:23974150
Wang, Wenyi; Wu, Renbiao
2013-01-01
DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy algorithms, have been recognized as a kind of novel DOA estimation algorithm. However, the success of these algorithms is limited by the RIP (Restricted Isometry Property) condition or the mutual coherence of measurement matrix. In the DOA estimation problem, the columns of measurement matrix are steering vectors corresponding to different DOAs. Thus, it violates the mutual coherence condition. The situation gets worse when there are two sources from two adjacent DOAs. In this paper, an algorithm based on OMP (Orthogonal Matching Pursuit), called ILS-OMP (Iterative Local Searching-Orthogonal Matching Pursuit), is proposed to improve DOA resolution by Iterative Local Searching. Firstly, the conventional OMP algorithm is used to obtain initial estimated DOAs. Then, in each iteration, a local searching process for every estimated DOA is utilized to find a new DOA in a given DOA set to further decrease the residual. Additionally, the estimated DOAs are updated by substituting the initial DOA with the new one. The simulation results demonstrate the advantages of the proposed algorithm. PMID:23974150
Unidirectional perfect absorber.
Jin, L; Wang, P; Song, Z
2016-01-01
This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices. PMID:27615125
Gilles, L; Ellerbroek, B L
2008-05-15
We recently introduced matched filtering in the context of astronomical Shack-Hartmann wavefront sensing with elongated sodium laser beacons [Appl. Opt. 45, 6568 (2006)]. Detailed wave optics Monte Carlo simulations implementing this technique for the Thirty Meter Telescope dual conjugate adaptive optics system have, however, revealed frequent bursts of degraded closed loop residual wavefront error [Proc. SPIE 6272, 627236 (2006)]. The origin of this problem is shown to be related to laser guide star jitter on the sky that kicks the filter out of its linear dynamic range, which leads to bursts of nonlinearities that are reconstructed into higher-order wavefront aberrations, particularly coma and trifoil for radially elongated subaperture spots. An elegant reformulation of the algorithm is proposed to extend its dynamic range using a set of linear constraints while preserving its improved noise rejection and Monte Carlo performance results are reported that confirm the benefits of the method. PMID:18483545
2013-01-01
Background If you want to know which of two or more healthcare interventions is most effective, the randomised controlled trial is the design of choice. Randomisation, however, does not itself promote the applicability of the results to situations other than the one in which the trial was done. A tool published in 2009, PRECIS (PRagmatic Explanatory Continuum Indicator Summaries) aimed to help trialists design trials that produced results matched to the aim of the trial, be that supporting clinical decision-making, or increasing knowledge of how an intervention works. Though generally positive, groups evaluating the tool have also found weaknesses, mainly that its inter-rater reliability is not clear, that it needs a scoring system and that some new domains might be needed. The aim of the study is to: Produce an improved and validated version of the PRECIS tool. Use this tool to compare the internal validity of, and effect estimates from, a set of explanatory and pragmatic trials matched by intervention. Methods The study has four phases. Phase 1 involves brainstorming and a two-round Delphi survey of authors who cited PRECIS. In Phase 2, the Delphi results will then be discussed and alternative versions of PRECIS-2 developed and user-tested by experienced trialists. Phase 3 will evaluate the validity and reliability of the most promising PRECIS-2 candidate using a sample of 15 to 20 trials rated by 15 international trialists. We will assess inter-rater reliability, and raters’ subjective global ratings of pragmatism compared to PRECIS-2 to assess convergent and face validity. Phase 4, to determine if pragmatic trials sacrifice internal validity in order to achieve applicability, will compare the internal validity and effect estimates of matched explanatory and pragmatic trials of the same intervention, condition and participants. Effect sizes for the trials will then be compared in a meta-regression. The Cochrane Risk of Bias scores will be compared with the
Epstein, Michael P; Duncan, Richard; Broadaway, K Alaine; He, Min; Allen, Andrew S; Satten, Glen A
2012-04-01
Proper control of confounding due to population stratification is crucial for valid analysis of case-control association studies. Fine matching of cases and controls based on genetic ancestry is an increasingly popular strategy to correct for such confounding, both in genome-wide association studies (GWASs) as well as studies that employ next-generation sequencing, where matching can be used when selecting a subset of participants from a GWAS for rare-variant analysis. Existing matching methods match on measures of genetic ancestry that combine multiple components of ancestry into a scalar quantity. However, we show that including nonconfounding ancestry components in a matching criterion can lead to inaccurate matches, and hence to an improper control of confounding. To resolve this issue, we propose a novel method that assigns cases and controls to matched strata based on the stratification score (Epstein et al. [2007] Am J Hum Genet 80:921-930), which is the probability of disease given genomic variables. Matching on the stratification score leads to more accurate matches because case participants are matched to control participants who have a similar risk of disease given ancestry information. We illustrate our matching method using the African-American arm of the GAIN GWAS of schizophrenia. In this study, we observe that confounding due to stratification can be resolved by our matching approach but not by other existing matching procedures. We also use simulated data to show our novel matching approach can provide a more appropriate correction for population stratification than existing matching approaches. PMID:22714934
ERIC Educational Resources Information Center
Hinshaw, Craig
2005-01-01
For thousands of years, the three perfections--painting, poetry, and calligraphy--have been considered the mark of an enlightened person throughout Asian cultures. Fifth-grade students learned about these three hallmarks by studying three works from the Detroit Institute of Art's Asian collection: a nineteenth-century Japanese hand scroll, a…
ERIC Educational Resources Information Center
Berry, John N., III
2010-01-01
The perfect politician, the ideal political ally to a library, is often but not always an elected official. He or she is always an effective champion of "reasonable financial support," i.e., "the amount...which a thoroughly competent librarian can spend wisely." That is what J.T. Wyer, director of the New York State Library, said in his "What the…
ERIC Educational Resources Information Center
Bacon, David
2010-01-01
The United States today faces an economic crisis worse than any since the Great Depression of the 1930s. Nowhere is it sharper than in the nation's schools. Last year, California saw a perfect storm of protest in virtually every part of its education system. K-12 teachers built coalitions with parents and students to fight for their jobs and their…
ERIC Educational Resources Information Center
Russo, Ruth
1998-01-01
A chemistry teacher describes the elements of the ideal chemistry textbook. The perfect text is focused and helps students draw a coherent whole out of the myriad fragments of information and interpretation. The text would show chemistry as the central science necessary for understanding other sciences and would also root chemistry firmly in the…
Larkin, Ivan A; Stockman, Mark I
2005-02-01
We have quantitatively established a fundamental limitation on the ultimate spatial resolution of the perfect lens (thin metal slab) in the near field. This limitation stems from the spatial dispersion of the dielectric response of the Fermi liquid of electrons with Coulomb interaction in the metal. We discuss possible applications in nanoimaging, nanophotolithography, and nanospectroscopy. PMID:15794622
ERIC Educational Resources Information Center
Murray, Jeannette
2010-01-01
In a perfect world, all children should live at home with their family, play with the kids in their neighborhood, walk or ride the school bus to a community-based school--after affectionately kissing or hugging their parents goodbye. They should receive adequate classroom services and return home at 3 p.m. or thereabouts. They may even…
Zhou, Jianying; Schepmoes, Athena A.; Zhang, Xu; Moore, Ronald J.; Monroe, Matthew E.; Lee, Jung Hwa; Camp, David G.; Smith, Richard D.; Qian, Weijun
2010-09-02
Spectral counting has become a popular semi-quantitative method for LC-MS/MS based proteome quantification; however, this methodology is often not reliable when proteins are identified by a small number of spectra. Here we present a simple strategy to improve spectral counting based quantification for low abundance proteins by recovering low quality or low scoring spectra for confidently identified peptides. In this approach, stringent data filtering criteria were initially applied to achieve confident peptide identifications with low false discovery rate (e.g., <1%) after LC-MS/MS analysis and database search by SEQUEST. Then, all low scoring MS/MS spectra that match to this set of confidently identified peptides were recovered, leading to more than 20% increase of total identified spectra. The validity of these recovered spectra was assessed by the parent ion mass measurement error distribution, retention time distribution, and by comparing the individual low score and high score spectra that correspond to the same peptides. The results support that the recovered low scoring spectra have similar confidence levels in peptide identifications as the spectra passing the initial stringent filter. The application of this strategy of recovering low scoring spectra significantly improved the spectral count quantification statistics for low abundance proteins, as illustrated in the identification of mouse brain region specific proteins.
Perfect Quantum Cosmological Bounce
NASA Astrophysics Data System (ADS)
Gielen, Steffen; Turok, Neil
2016-07-01
We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous, isotropic backgrounds, we are able to perform the quantum gravity path integral exactly. The evolution describes a "perfect bounce", in which the Universe passes smoothly through the singularity. We extend the analysis to spatially flat, anisotropic universes, treated exactly, and to generic inhomogeneous, anisotropic perturbations treated at linear and nonlinear order. This picture provides a natural, unitary description of quantum mechanical evolution across a cosmological bounce. We provide evidence for a semiclassical description in which all fields pass "around" the cosmological singularity along complex classical paths.
Perfect Quantum Cosmological Bounce.
Gielen, Steffen; Turok, Neil
2016-07-01
We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous, isotropic backgrounds, we are able to perform the quantum gravity path integral exactly. The evolution describes a "perfect bounce", in which the Universe passes smoothly through the singularity. We extend the analysis to spatially flat, anisotropic universes, treated exactly, and to generic inhomogeneous, anisotropic perturbations treated at linear and nonlinear order. This picture provides a natural, unitary description of quantum mechanical evolution across a cosmological bounce. We provide evidence for a semiclassical description in which all fields pass "around" the cosmological singularity along complex classical paths. PMID:27447496
BNL
2009-09-01
Evidence to date suggests that gold-gold collisions the Relativistic Heavy Ion Collider at Brookhaven are indeed creating a new state of hot, dense matter, but one quite different and even more remarkable than had been predicted. Instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions appears to be more like a "perfect" liquid.
Guild, Georgia E; Stangoulis, James C R
2016-01-01
Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644
Guild, Georgia E.; Stangoulis, James C. R.
2016-01-01
Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644
ERIC Educational Resources Information Center
Lazorick, Suzanne; Fang, Xiangming; Hardison, George T.; Crawford, Yancey
2015-01-01
Background: Motivating Adolescents with Technology to CHOOSE Health™ (MATCH) is an educational and behavioral intervention in seventh grade. Methods: Teachers in 2 schools delivered the MATCH curriculum, with 1 control school. Using a quasi-experimental design, outcome measures included lessons completed, body mass index (BMI), BMI z-score (zBMI),…
Elhence, Priti; Chaudhary, Rajendra K.; Nityanand, Soniya
2014-01-01
Background Cross-match-compatible platelets are used for the management of thrombocytopenic patients who are refractory to transfusions of randomly selected platelets. Data supporting the effectiveness of platelets that are compatible according to cross-matching with a modified antigen capture enzyme-linked immunosorbent assay (MAC-ELISA or MACE) are limited. This study aimed to determine the effectiveness of cross-match-compatible platelets in an unselected group of refractory patients. Materials and methods One hundred ABO compatible single donor platelet transfusions given to 31 refractory patients were studied. Patients were defined to be refractory if their 24-hour corrected count increment (CCI) was <5×109/L following two consecutive platelet transfusions. Platelets were cross-matched by MACE and the CCI was determined to monitor the effectiveness of platelet transfusions. Results The clinical sensitivity, specificity, positive predictive value and negative predictive value of the MACE-cross-matched platelets for post-transfusion CCI were 88%, 54.6%, 39.3% and 93.2%, respectively. The difference between adequate and inadequate post-transfusion 24-hour CCI for MACE cross-matched-compatible vs incompatible single donor platelet transfusions was statistically significant (p=0.000). The 24-hour CCI (mean±SD) was significantly higher for cross-match-compatible platelets (9,250±026.6) than for incompatible ones (6,757.94±2,656.5) (p<0.0001). Most of the incompatible cross-matches (73.2%) were due to anti-HLA antibodies, alone (55.3% of cases) or together with anti-platelet glycoprotein antibodies (17.9%). Discussion The clinical sensitivity and negative predictive value of platelet cross-matching by MACE were high in this study and such tests may, therefore, be used to select compatible platelets for refractory patients. A high negative predictive value demonstrates the greater chance of an adequate response with cross-matched-compatible platelets. PMID
Ultra-Perfect Sorting Scenarios
NASA Astrophysics Data System (ADS)
Ouangraoua, Aïda; Bergeron, Anne; Swenson, Krister M.
Perfection has been used as a criteria to select rearrangement scenarios since 2004. However, there is a fundamental bias towards extant species in the original definition: ancestral species are not bound to perfection. Here we develop a new theory of perfection that takes an egalitarian view of species, and apply it to the complex evolution of mammal chromosome X.
Nuclear Forces and High-Performance Computing: The Perfect Match
Luu, T; Walker-Loud, A
2009-06-12
High-performance computing is now enabling the calculation of certain nuclear interaction parameters directly from Quantum Chromodynamics, the quantum field theory that governs the behavior of quarks and gluons and is ultimately responsible for the nuclear strong force. We briefly describe the state of the field and describe how progress in this field will impact the greater nuclear physics community. We give estimates of computational requirements needed to obtain certain milestones and describe the scientific and computational challenges of this field.
A perfect match: Nuclear energy and the National Energy Strategy
Not Available
1990-11-01
In the course of developing the National Energy Strategy, the Department of Energy held 15 public hearings, heard from more than 375 witnesses and received more than 1000 written comments. In April 1990, the Department published an Interim Report on the National Energy Strategy, which compiles those public comments. The National Energy Strategy must be based on actual experience and factual analysis of our energy, economic and environmental situation. This report by the Nuclear Power Oversight committee, which represents electric utilities and other organizations involved in supplying electricity from nuclear energy to the American people, provides such an analysis. The conclusions here are based on hard facts and actual worldwide experience. This analysis of all the available data supports -- indeed, dictates -- expanded reliance on nuclear energy in this nation's energy supply to achieve the President's goals. 33 figs.
Soil Respiration and Student Inquiry: A Perfect Match
ERIC Educational Resources Information Center
Hoyt, Catherine Marie; Wallenstein, Matthew David
2011-01-01
This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…
Literature Circles: A Perfect Match for Online Instruction
ERIC Educational Resources Information Center
Whittingham, Jeff
2013-01-01
This article describes the author's search for an appropriate and satisfying online teaching method. After experimenting with several methods (chat room, discussion board, student led discussion), the author reached back to his face-to-face classroom success with literature circles. This article reports the results of research conducted by the…
Literacy Design Collaborative and Struggling Readers: A Perfect Match
ERIC Educational Resources Information Center
Southern Regional Education Board (SREB), 2014
2014-01-01
In Florida, middle grades students take the Florida Comprehensive Assessment Test 2.0 (FCAT 2.0) in reading and writing. In partnership with the Southern Regional Education Board (SREB), Avalon Middle School implemented the Literacy Design Collaborative (LDC) framework beginning in the 2012-2013 school year to develop literacy skills across…
Coherent perfect absorption in nonlinear optics
NASA Astrophysics Data System (ADS)
Zheng, Yuanlin; Wan, Wenjie; Chen, Xianfeng
2013-02-01
Recently, a concept of time reversed lasing or coherent perfect absorber (CPA) has been proposed by A. D. Stone and co-workers, and was shortly experimentally demonstrated by them. The CPA system is illuminated coherently and monochromatically by the time reverse of the output of a lasing mode and the incident radiation is perfectly absorbed. Shortly afterwards, Stefano Longhi extended the idea to realize a CPA for colored incident light, and have theoretically shown that the time reversal of optical parametric oscillation (OPO) in a nonlinear medium could also realize a colored CPA for incident signal and idler fields which can be seemed as a kind of nonlinear CPA. Here we present the realization of such time-reversed processes in nonlinear optics regime, including time-reversed second harmonic generation (SHG) for coherent absorption at harmonic frequency of the pump and time-reversed optical parametric amplification (OPA) for coherent attenuation of colored travelling optical fields. Time reversed SHG is carried out at both phase matching and mismatching conditions, which shows parametric near perfect absorption at the harmonic frequency of the pump. The time reversal of OPA is demonstrated experimentally in a nonlinear medium to form a coherent absorber for perpendicularly polarized signal and idler travelling waves, realizing in the condition of OPA by a type II phase matching scheme. The absorption of signal/idler pair occurs at some specific phase difference. This is the first experimental demonstration of coherent absorption processes in nonlinear optics regime.
Lampit, Amit; Ebster, Claus; Valenzuela, Michael
2014-01-01
Cognitive skills are important predictors of job performance, but the extent to which computerized cognitive training (CCT) can improve job performance in healthy adults is unclear. We report, for the first time, that a CCT program aimed at attention, memory, reasoning and visuo-spatial abilities can enhance productivity in healthy younger adults on bookkeeping tasks with high relevance to real-world job performance. 44 business students (77.3% female, mean age 21.4 ± 2.6 years) were assigned to either (a) 20 h of CCT, or (b) 20 h of computerized arithmetic training (active control) by a matched sampling procedure. Both interventions were conducted over a period of 6 weeks, 3–4 1-h sessions per week. Transfer of skills to performance on a 60-min paper-based bookkeeping task was measured at three time points—baseline, after 10 h and after 20 h of training. Repeated measures ANOVA found a significant Group X Time effect on productivity (F = 7.033, df = 1.745; 73.273, p = 0.003) with a significant interaction at both the 10-h (Relative Cohen's effect size = 0.38, p = 0.014) and 20-h time points (Relative Cohen's effect size = 0.40, p = 0.003). No significant effects were found on accuracy or on Conners' Continuous Performance Test, a measure of sustained attention. The results are discussed in reference to previous findings on the relationship between brain plasticity and job performance. Generalization of results requires further study. PMID:25120510
Lampit, Amit; Ebster, Claus; Valenzuela, Michael
2014-01-01
Cognitive skills are important predictors of job performance, but the extent to which computerized cognitive training (CCT) can improve job performance in healthy adults is unclear. We report, for the first time, that a CCT program aimed at attention, memory, reasoning and visuo-spatial abilities can enhance productivity in healthy younger adults on bookkeeping tasks with high relevance to real-world job performance. 44 business students (77.3% female, mean age 21.4 ± 2.6 years) were assigned to either (a) 20 h of CCT, or (b) 20 h of computerized arithmetic training (active control) by a matched sampling procedure. Both interventions were conducted over a period of 6 weeks, 3-4 1-h sessions per week. Transfer of skills to performance on a 60-min paper-based bookkeeping task was measured at three time points-baseline, after 10 h and after 20 h of training. Repeated measures ANOVA found a significant Group X Time effect on productivity (F = 7.033, df = 1.745; 73.273, p = 0.003) with a significant interaction at both the 10-h (Relative Cohen's effect size = 0.38, p = 0.014) and 20-h time points (Relative Cohen's effect size = 0.40, p = 0.003). No significant effects were found on accuracy or on Conners' Continuous Performance Test, a measure of sustained attention. The results are discussed in reference to previous findings on the relationship between brain plasticity and job performance. Generalization of results requires further study. PMID:25120510
NASA Astrophysics Data System (ADS)
Charoen-In, Urit; Ramasamy, P.; Manyum, P.
2013-01-01
A single crystal of dichlorobis(L-proline)zinc(II) (LPZ) was successfully grown by the Sankaranarayanan-Ramasamy (SR) method and conventional slow evaporation solution technique (SEST). The lattice parameters of the grown LPZ crystal were confirmed by single crystal X-ray diffraction. The morphology of the conventional method grown LPZ crystal was identified. HRXRD analysis indicates that the crystalline perfections of the grown crystals are excellent without having any low angle internal structural grain boundaries. Etch pit density of the conventional and SR method grown LPZ crystals were calculated. Piezoelectric d33 coefficient of the SR method grown crystal were higher than the conventional method grown LPZ crystal. The dielectric constant and loss measurements were made as a function of temperature in the range between 40 °C and 140 °C. A low value of dielectric loss was observed in the SR method grown crystal. The obtained transparency for the crystals grown by the SR and conventional methods are 71% and 60%, respectively in the entire visible region. Microhardness measurements revealed the mechanical strength of the grown crystal. Second harmonic generation (SHG) measurement indicates that the SHG efficiency of the grown LPZ crystal was equal to that of KDP crystals.
2015-01-01
Background Continued advances in next generation short-read sequencing technologies are increasing throughput and read lengths, while driving down error rates. Taking advantage of the high coverage sampling used in many applications, several error correction algorithms have been developed to improve data quality further. However, correcting errors in high coverage sequence data requires significant computing resources. Methods We propose a different approach to handle erroneous sequence data. Presently, error rates of high-throughput platforms such as the Illumina HiSeq are within 1%. Moreover, the errors are not uniformly distributed in all reads, and a large percentage of reads are indeed error-free. Ability to predict such perfect reads can significantly impact the run-time complexity of applications. We present a simple and fast k-spectrum analysis based method to identify error-free reads. The filtration process to identify and weed out erroneous reads can be customized at several levels of stringency depending upon the downstream application need. Results Our experiments show that if around 80% of the reads in a dataset are perfect, then our method retains almost 99.9% of them with more than 90% precision rate. Though filtering out reads identified as erroneous by our method reduces the average coverage by about 7%, we found the remaining reads provide as uniform a coverage as the original dataset. We demonstrate the effectiveness of our approach on an example downstream application: we show that an error correction algorithm, Reptile, which rely on collectively analyzing the reads in a dataset to identify and correct erroneous bases, instead use reads predicted to be perfect by our method to correct the other reads, the overall accuracy improves further by up to 10%. Conclusions Thanks to the continuous technological improvements, the coverage and accuracy of reads from dominant sequencing platforms have now reached an extent where we can envision just
Smith, Graham D.; Pickles, Tom; Crook, Juanita; Martin, Andre-Guy; Vigneault, Eric; Cury, Fabio L.; Morris, Jim; Catton, Charles; Lukka, Himu; Warner, Andrew; Yang, Ying; Rodrigues, George
2015-03-01
Purpose: To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. Methods and Materials: Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2) intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups. Results: Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500). Conclusions: Propensity score matched analysis showed that BT options led
Bril, V
2016-01-01
Multiple phase III clinical trials have failed to show disease-modifying benefits for diabetic sensorimotor polyneuropathy (DSP) and this may be due to the design of the clinical trials. The perfect clinical trial in DSP would enroll sufficiently large numbers of patients having early or minimal disease, as demonstrated by nerve conduction studies (NCS). These patients would be treated with an intervention given at an effective and well-tolerated dose for a sufficient duration of time to show change in the end points selected. For objective or surrogate measures such as NCS and for some small fiber measures, the duration needed to show positive change may be as brief as 6-12 months, but subsequently, trials lasting 5-8 years will be required to demonstrate clinical benefits. PMID:27133143
NASA Technical Reports Server (NTRS)
2000-01-01
Billows of smoke and steam spread across Launch Pad 39A as Space Shuttle Discovery lifts off on mission STS-92 to the International Space Station. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.
Moulton, Calum
2014-10-01
Perfect pitch, or absolute pitch (AP), is defined as the ability to identify or produce the pitch of a sound without need for a reference pitch, and is generally regarded as a valuable asset to the musician. However, there has been no recent review of the literature examining its aetiology and its utility taking into account emerging scientific advances in AP research, notably in functional imaging. This review analyses the key empirical research on AP, focusing on genetic and neuroimaging studies. The review concludes that: AP probably has a genetic predisposition, although this is based on limited evidence; early musical training is almost certainly essential for AP acquisition; and, although there is evidence that it may be relevant to speech processing, AP can interfere with relative pitch, an ability on which humans rely to communicate effectively. The review calls into question the value of AP to musicians and non-musicians alike. PMID:25301913
ERIC Educational Resources Information Center
Chi, Olivia L.; Dow, Aaron W.
2014-01-01
This study focuses on how matching, a method of preprocessing data prior to estimation and analysis, can be used to reduce imbalance between treatment and control group in regression discontinuity design. To examine the effects of academic probation on student outcomes, researchers replicate and expand upon research conducted by Lindo, Sanders,…
Four-wave interference and perfect blaze.
Güther, R
2012-10-01
The recently calculated high diffraction efficiencies for TE- and TM-polarized light (perfect blaze) for echelette gratings are explained by four-wave interference, which is formed as a double periodical pattern in the cross section of the grating plane. The blazed grating profile should match this interference pattern for a single reference light wavelength. The recently published data are the special case of a general design. The prognoses of the model are connected with large grating constants in comparison with the light wavelength, where short grating constants need comparison with numerical methods. PMID:23027283
Perfect anti-reflection from first principles
NASA Astrophysics Data System (ADS)
Kim, Kyoung-Ho; Q-Han Park
2013-01-01
Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.
Foley, C L; Mould, T; Kennedy, J E; Barton, D P J
2003-01-01
The objective of this study was to design and implement a maximum surgical blood order schedule (MSBOS) within a specialist gynecological oncology department in a tertiary referral center and evaluate its impact on the cross-match to transfusion ratio (CTR). A retrospective case note audit was undertaken to identify common operations performed within the unit and their transfusion requirements. The efficiency of blood usage was assessed using the CTR, and an MSBOS was devised and implemented. A prospective audit of preoperative blood cross-matching and subsequent blood usage was then performed for consecutive elective operations in the unit, to assess the effect of the MSBOS. The retrospective study of 222 cases demonstrated a CTR of 2.25 equivalent to 44% usage of cross-matched blood. Ninety two percent of operations performed within the unit could be incorporated into an MSBOS. The prospective study of 207 cases demonstrated a significantly reduced CTR of 1.71 or 59% blood usage (chi2 = 12.4, P < 0.001). This equates to a saving of 102 units of blood over the 15 months prospective audit. Protocol adherence was 77%. No patient was adversely affected by the adoption of the MSBOS. We conclude that an MSBOS can be safely introduced into a gynecological oncology department resulting in significant financial savings. PMID:14675329
TEACHING THE PRESENT PERFECT TENSES.
ERIC Educational Resources Information Center
WALKER, RALPH H.
THE SIMPLE PRESENT PERFECT AND PRESENT PERFECT CONTINUOUS ARE FOR THE NON-NATIVE SPEAKER OF ENGLISH TWO OF THE MOST TROUBLESOME TENSES IN THE ENGLISH VERB SYSTEM. THEY ARE SOMETIMES CONFUSED WITH A PRESENT TENSE AND SOMETIMES WITH A PAST. ONE OFTEN HEARS A NON-NATIVE SPEAKER OF ENGLISH USE A SIMPLE PRESENT WHERE HE SHOULD USE A SIMPLE PRESENT…
Chen, Di-Ming; Tian, Jia-Yue; Liu, Chun-Sen; Du, Miao
2016-06-28
Incorporating the in situ formed size-matching molecular building blocks (MBBs) into the open channels will remarkably improve the robustness and gas sorption performance of an evacuated metal-organic framework. As a result, such MBBs can transfer the open metal sites from the framework walls to the channel centers and separate the large channels into multiple smaller voids, leading to a molecular sieving effect and high-performance gas-separation of the modified material. PMID:27301546
The Perfective Past Tense in Greek Adolescents with Down Syndrome
ERIC Educational Resources Information Center
Stathopoulou, Nikolitsa; Clahsen, Harald
2010-01-01
This study investigates the ability of a group of eight Greek-speaking adolescents with Down Syndrome (DS) (aged 12.1-18.7) to handle the perfective past tense using an acceptability judgement task. The performance of the DS participants was compared with that of 16 typically-developing children whose chronological age was matched with the mental…
NASA Astrophysics Data System (ADS)
Hursky, Paul
2001-07-01
This dissertation describes matched field source localization methods in a shallow water ocean waveguide which overcome lack of knowledge of the waveguide properties, whose measurement would otherwise be essential for conventional matched field methods to succeed. Such measurements are typically obtained only at great cost by dedicated measurement platforms, separate and distinct from the sensors used to localize sources. We demonstrate MFP using modes derived from data, the sound speed profile, but no a priori bottom information. We show how mode shapes can be estimated directly from vertical line array data, without a priori knowledge of the environment and without using numerical wavefield models. However, it is difficult to make much headway with modes derived from data, without wave numbers, since only a few modes at a few frequencies may be captured, and only at depths sampled by the array. Using a measured sound speed profile, we derive self-consistent, complete sets of modes, wave numbers and bottom parameters from incomplete modes derived from data. Bottom parameters enable us to calculate modes at all frequencies, not just those at which we derived modes from data. This process is applied to SWellEx-96 experiment data. Modes, wave numbers and bottom parameters are derived from source tow data along one track and MFP based on this information is performed on source tow data along another track.
Theiler, James P
2009-01-01
Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.
The P.F.C. sigma RP-F TKA designed for improved performance: a matched-pair study.
Gupta, Sanjay K; Ranawat, Amar S; Shah, Vineet; Zikria, Bashir A; Zikria, Joseph F; Ranawat, Chitranjan S
2006-09-01
The press fit condylar P.F.C. Sigma RP-F (rotating-platform, high flexion) knee is designed to provide a range of motion (ROM) of 155 degrees without compromising wear, polyethylene contact stresses, patellofemoral tracking, or stability. The first 50 TKA surgeries using the Sigma RP-F knee performed at the author's institution were matched to 50 rotating-platform knees for age, sex, body mass index, preoperative diagnosis, duration of follow-up, and preoperative ROM to determine the effect of design on postoperative ROM. The mean increase in active ROM in the Sigma RP-F group was 17 degrees, compared with 6 degrees in the rotating-platform group (P =.0011). The mean increase in active ROM in patients who had less than 120 degrees of preoperative motion was 27 degrees in the Sigma RP-F group, compared with 16 degrees in the rotating-platform group (P = .006). With the new P.F.C. Sigma RP-F design, greater ROM can be achieved independent of preoperative ROM. PMID:17002149
Roberto, Megan E.; Brumley, Michele R.
2014-01-01
The amount of postnatal experience for perinatal rats was manipulated by delivering pups one day early (postconception day 21; PC21) by cesarean delivery and comparing their motor behavior to age-matched controls on PC22 (the typical day of birth). On PC22, pups were tested on multiple measures of motor coordination: leg extension response (LER), facial wiping, contact righting, and fore- and hindlimb stepping. The LER and facial wiping provided measures of synchronous hind- and forelimb coordination, respectively, and were sensory-evoked. Contact righting also was sensory-evoked and provided a measure of axial coordination. Stepping provided a measure of alternated forelimb and hindlimb coordination and was induced with the serotonin receptor agonist quipazine. Pups that were delivered prematurely and spent an additional day in the postnatal environment showed more bilateral limb coordination during expression of the LER and facial wiping, as well as a more mature righting strategy, compared to controls. These findings suggest that experience around the time of birth shapes motor coordination and the expression of species-typical behavior in the developing rat. PMID:24680729
NASA Astrophysics Data System (ADS)
2008-05-01
ESO celebrates 10 years since First Light of the VLT Today marks the 10th anniversary since First Light with ESO's Very Large Telescope (VLT), the most advanced optical telescope in the world. Since then, the VLT has evolved into a unique suite of four 8.2-m Unit Telescopes (UTs) equipped with no fewer than 13 state-of-the-art instruments, and four 1.8-m moveable Auxiliary Telescopes (ATs). The telescopes can work individually, and they can also be linked together in groups of two or three to form a giant 'interferometer' (VLTI), allowing astronomers to see details corresponding to those from a much larger telescope. Green Flash at Paranal ESO PR Photo 16a/08 The VLT 10th anniversary poster "The Very Large Telescope array is a flagship facility for astronomy, a perfect science machine of which Europe can be very proud," says Tim de Zeeuw, ESO's Director General. "We have built the most advanced ground-based optical observatory in the world, thanks to the combination of a long-term adequately-funded instrument and technology development plan with an approach where most of the instruments were built in collaboration with institutions in the member states, with in-kind contributions in labour compensated by guaranteed observing time." Sitting atop the 2600m high Paranal Mountain in the Chilean Atacama Desert, the VLT's design, suite of instruments, and operating principles set the standard for ground-based astronomy. It provides the European scientific community with a telescope array with collecting power significantly greater than any other facilities available at present, offering imaging and spectroscopy capabilities at visible and infrared wavelengths. Blue Flash at Paranal ESO PR Photo 16b/08 A Universe of Discoveries The first scientifically useful images, marking the official 'First Light' of the VLT, were obtained on the night of 25 to 26 May 1998, with a test camera attached to "Antu", Unit Telescope number 1. They were officially presented to the press on
Majhi, S.K.; Mukhopadhyay, A.; Ward, B.F.L.; Yost, S.A.
2014-11-15
We present a phenomenological study of the current status of the application of our approach of exact amplitude-based resummation in quantum field theory to precision QCD calculations, by realistic MC event generator methods, as needed for precision LHC physics. We discuss recent results as they relate to the interplay of the attendant IR-improved DGLAP-CS theory of one of us and the precision of exact NLO matrix-element matched parton shower MC’s in the Herwig6.5 environment as determined by comparison to recent LHC experimental observations on single heavy gauge boson production and decay. The level of agreement between the new theory and the data continues to be a reason for optimism. In the spirit of completeness, we discuss as well other approaches to the same theoretical predictions that we make here from the standpoint of physical precision with an eye toward the (sub-)1% QCD⊗EW total theoretical precision regime for LHC physics. - Highlights: • Using LHC data, we show that IR-improved DGLAP-CS kernels with exact NLO Shower/ME matching improves MC precision. • We discuss other possible approaches in comparison with ours. • We propose experimental tests to discriminate between competing approaches.
Shi, X; Lin, J; Diwanji, T; Mooney, K; D'Souza, W; Mistry, N
2014-06-01
Purpose: Recently, template matching has been shown to be able to track tumor motion on cine-MRI images. However, artifacts such as deformation, rotation, and/or out-of-plane movement could seriously degrade the performance of this technique. In this work, we demonstrate the utility of multiple templates derived from different phases of tumor motion in reducing the negative effects of artifacts and improving the accuracy of template matching methods. Methods: Data from 2 patients with large tumors and significant tumor deformation were analyzed from a group of 12 patients from an earlier study. Cine-MRI (200 frames) imaging was performed while the patients were instructed to breathe normally. Ground truth tumor position was established on each frame manually by a radiation oncologist. Tumor positions were also automatically determined using template matching with either single or multiple (5) templates. The tracking errors, defined as the absolute differences in tumor positions determined by the manual and automated methods, when using either single or multiple templates were compared in both the AP and SI directions, respectively. Results: Using multiple templates reduced the tracking error of template matching. In the SI direction where the tumor movement and deformation were significant, the mean tracking error decreased from 1.94 mm to 0.91 mm (Patient 1) and from 6.61 mm to 2.06 mm (Patient 2). In the AP direction where the tumor movement was small, the reduction of the mean tracking error was significant in Patient 1 (from 3.36 mm to 1.04 mm), but not in Patient 2 ( from 3.86 mm to 3.80 mm). Conclusion: This study shows the effectiveness of using multiple templates in improving the performance of template matching when artifacts like large tumor deformation or out-of-plane motion exists. Accurate tumor tracking capabilities can be integrated with MRI guided radiation therapy systems. This work was supported in part by grants from NIH/NCI CA 124766 and Varian
NASA Astrophysics Data System (ADS)
Park, Jun-Hyub; Shin, Myung-Soo; Kang, Dong-Joong; Lim, Sung-Jo; Ha, Jong-Eun
In this study, a system for non-contact in-situ measurement of strain during tensile test of thin films by using CCD camera with marking surface of specimen by black pen was implemented as a sensing device. To improve accuracy of measurement when CCD camera is used, this paper proposed a new method for measuring strain during tensile test of specimen with micrometer size. The size of pixel of CCD camera determines resolution of measurement, but the size of pixel can not satisfy the resolution required in tensile test of thin film because the extension of the specimen is very small during the tensile test. To increase resolution of measurement, the suggested method performs an accurate subpixel matching by applying 2nd order polynomial interpolation method to the conventional template matching. The algorithm was developed to calculate location of subpixel providing the best matching value by performing single dimensional polynomial interpolation from the results of pixel-based matching at a local region of image. The measurement resolution was less than 0.01 times of original pixel size. To verify the reliability of the system, the tensile test for the BeNi thin film was performed, which is widely used as a material in micro-probe tip. Tensile tests were performed and strains were measured using the proposed method and also the capacitance type displacement sensor for comparison. It is demonstrated that the new strain measurement system can effectively describe a behavior of materials after yield during the tensile test of the specimen at microscale with easy setup and better accuracy.
Hogan, A. M.
2008-01-01
Extensive literature supports the correlation between surgical volume and improved clinical outcome in the management of various cancers. It is this evidence that has catalysed the creation of centres of excellence. However, on closer inspection, many of these studies are poor quality, low weight and use vastly heterogenous end points in assessment of both volume and outcome. We critically appraise the English language literature published over the last ten years pertaining to the volume outcome relationship in the context of cancer care. Future balanced unbiased studies may enable equipoise in planning international cancer management strategies. PMID:18228105
ERIC Educational Resources Information Center
Sadler, Jackie
Ways of improving the quality of precourse information, advice, and guidance available to students entering further education and sixth form colleges in the United Kingdom were explored. Data were collected from the following sources: (1) the 3-year Raising Quality and Achievement Programme; (2) seminars on sharing good practice in delivering…
NASA Astrophysics Data System (ADS)
Clifford, Raphael; Harrow, Aram W.; Popa, Alexandru; Sach, Benjamin
Given a pattern p over an alphabet Σ p and a text t over an alphabet Σ t , we consider the problem of determining a mapping f from Σ p to {Σ}t+ such that t = f(p 1)f(p 2)...f(p m ). This class of problems, which was first introduced by Amir and Nor in 2004, is defined by different constraints on the mapping f. We give NP-Completeness results for a wide range of conditions. These include when f is either many-to-one or one-to-one, when Σ t is binary and when the range of f is limited to strings of constant length. We then introduce a related problem we term pattern matching with string classes which we show to be solvable efficiently. Finally, we discuss an optimisation variant of generalised matching and give a polynomial-time min (1,sqrt{k/OPT})-approximation algorithm for fixed k.
Imamura, Teruhiko; Kinugawa, Koichiro; Sakata, Yasushi; Miyagawa, Shigeru; Sawa, Yoshiki; Yamazaki, Kenji; Ono, Minoru
2016-03-01
We recently reported a multi-center, single-arm, phase II study that evaluated the efficacy and safety of autologous skeletal myoblast sheet (TCD-51073) transplantation. The advantage of this procedure over a control group has not yet been analyzed. Seven patients with advanced heart failure due to ischemic etiology (TCD-51073 group, New York Heart Association (NYHA) class III; left ventricular ejection fraction (LVEF) <35 %) refractory to optimal medical and coronary revascularization therapy, received TCD-51073 at 3 study centers between 2012 and 2013 with a 2-year follow-up period. As previously reported, 112 patients received cardiac resynchronization therapy (CRT) with follow-up at the University of Tokyo Hospital between 2007 and 2014. Of them, 21 patients were selected for the control group by propensity score matching. No significant difference in baseline variables between the groups was observed. LVEF and NYHA class improved significantly in the TCD-51073 group during the 6-month study period (p < 0.05). During the 2-year follow-up, 7 patients (33 %) in the CRT group and no patient in the TCD-51073 group died due to cardiac disease or received VAD implantation (p = 0.128 by the log-rank test). In conclusion, transplantation of TCD-51073 is clinically advantageous in facilitating LV reverse remodeling, improving HF symptoms, and preventing cardiac death in patients with ischemic etiology when compared to background-matched patients receiving CRT. PMID:26267666
Group-Velocity-Matched Three Wave Mixing in Birefringent Crystals
SMITH,ARLEE V.
2000-12-12
We show that the combination of pulse-front slant, k-vector tilt, and crystal birefringence often permits exact matching of both phase and group velocities in three wave mixing in birefringent crystals. This makes possible more efficient mixing of short light pulses, and it permits efficient mixing of chirped or broad bandwidth light. We analyze this process and present examples. Differences in the group velocities of the three interacting waves in a nonlinear crystal often limits the effective interaction length. For example, in mixing very short pulses, temporal walk off can stretch the pulses in time unless the crystal is very short. Efficient mixing with such short crystals requires high irradiances, but the irradiances are limited by higher order nonlinear effects such as intensity-dependent refractive index and two-photon absorption. Improved matching of the group velocities can alleviate this problem, allowing longer crystal and lower irradiances. Similarly, for high energy pulses, practical limits on crystal apertures mandate temporally stretching the pulses to reduce irradiances. For the resulting chirped pulses, temporal walk off restricts the chirp range unless the group velocities are well matched. In addition to perfectly matching the group velocities of all three waves, it is sometimes useful to match two velocities, such as the signal and idler in parametric amplification, permitting broadband parametric amplification, or to arrange the velocities of two inputs to bracket the generated sum frequency pulse, giving pulse compression under suitable circumstances.
Perfect conformal invisible device with feasible refractive indexes
NASA Astrophysics Data System (ADS)
Xu, Lin; Chen, Huanyang; Tyc, Tomáš; Xie, Yangbo; Cummer, Steven A.
2016-01-01
Optical conformal mapping has been used to construct several isotropic devices with novel functionalities. In particular, a conformal cloak could confer omnidirectional invisibility. However, the maximum values of the refractive indexes needed for current designs are too large to implement, even in microwave experiments. Furthermore, most devices designed so far have had imperfect impedance matching and therefore incomplete invisibility functionalities. Here we describe a perfect conformal invisible device with full impedance matching everywhere. The maximum value of refractive index required by our device is just about five, which is feasible for microwave and terahertz experiments using current metamaterial techniques. To construct the device, we use a logarithmic conformal mapping and a Mikaelian lens. Our results should enable a conformal invisible device with almost perfect invisibility to be made soon.
Gill, M D; Bramble, M G; Hull, M A; Mills, S J; Morris, E; Bradburn, D M; Bury, Y; Parker, C E; Lee, T J W; Rees, C J
2014-01-01
Background: Colorectal cancers (CRCs) detected through the NHS Bowel Cancer Screening Programme (BCSP) have been shown to have a more favourable outcome compared to non-screen-detected cancers. The aim was to identify whether this was solely due to the earlier stage shift of these cancers, or whether other factors were involved. Methods: A combination of a regional CRC registry (Northern Colorectal Cancer Audit Group) and the BCSP database were used to identify screen-detected and interval cancers (diagnosed after a negative faecal occult blood test, before the next screening round), diagnosed between April 2007 and March 2010, within the North East of England. For each Dukes' stage, patient demographics, tumour characteristics, and survival rates were compared between these two groups. Results: Overall, 322 screen-detected cancers were compared against 192 interval cancers. Screen-detected Dukes' C and D CRCs had a superior survival rate compared with interval cancers (P=0.014 and P=0.04, respectively). Cox proportional hazards regression showed that Dukes' stage, tumour location, and diagnostic group (HR 0.45, 95% CI 0.29–0.69, P<0.001 for screen-detected CRCs) were all found to have a significant impact on the survival of patients. Conclusions: The improved survival of screen-detected over interval cancers for stages C and D suggest that there may be a biological difference in the cancers in each group. Although lead-time bias may have a role, this may be related to a tumour's propensity to bleed and therefore may reflect detection through current screening tests. PMID:25247322
Perfect absorbers for electromagnetic wave, based on metamaterials
NASA Astrophysics Data System (ADS)
Yoo, Young Joon; Kim, Young Ju; Lee, YoungPak
2015-10-01
Metamaterials (MMs), which are not existing in nature, but artificially-engineered materials for controlling electromagnetic wave. MMs have attracted more and more research attentions, since they have shown greatly novel properties such as left-handed behavior, negative refractive index, classical analog of electromagnetically-induced transparency, and extraordinary transmission. Among MMs, MM perfect absorbers (MMPAs), which are useful to enhance the efficiency in capturing solar energy and applied to various application areas, have been rapidly developed. In general, the structure of MMPAs is very simple, which consist of three layers: patterned conductor layer, which is used for minimizing the reflection by impedance matching, dielectric layer and continuous conductor layer for blocking the transmission. In addition, the unit-cell size of general MM absorbers is only 1/3-1/5 of the working wavelength of incident electromagnetic wave. Nevertheless, the properties of general MMPAs are in problems of the absorption only at specific frequency, the narrow absorption band, the polarization sensitivity and so on. In this review paper, the introduction of recent researches in the field of MMPAs operating in different frequency ranges is presented. Moreover, the researches on the improved electromagnetic properties are discussed, which comprise multi-band, broadband, tunable, polarization-insensitive, and wide-incident-angle MMPAs. The perspectives and the future works for the further investigations and the various real applications of MMPAs are also presented.
A perfect launch on a perfect Florida day!
NASA Technical Reports Server (NTRS)
2000-01-01
A perfect launch on a perfect Florida day! Framed by two immense billows of steam, Space Shuttle Endeavour breaks its Earthly tethers to soar into a clear blue sky. Liftoff of mission STS-99 occurred at 12:43:40 p.m. EST. Known as the Shuttle Radar Topography Mission (SRTM), STS-99 will chart a new course to produce unrivaled 3-D images of the Earth's surface. The result of the SRTM could be close to 1 trillion measurements of the Earth's topography. The mission is expected to last 11days, with Endeavour landing at KSC Tuesday, Feb. 22, at 4:36 p.m. EST. This is the 97th Shuttle flight and 14th for Shuttle Endeavour.
A perfect launch on a perfect Florida day!
NASA Technical Reports Server (NTRS)
2000-01-01
A perfect launch on a perfect Florida day! Space Shuttle Endeavour, with its crew of five, scatters billows of steam and smoke as it lifts off at 12:43:40 p.m. EST on mission STS-99. Employees and visitors watch intently from across the turn basin. Known as the Shuttle Radar Topography Mission (SRTM), STS-99 will chart a new course to produce unrivaled 3-D images of the Earth's surface. The result of the SRTM could be close to 1 trillion measurements of the Earth's topography. The mission is expected to last 11days, with Endeavour landing at KSC Tuesday, Feb. 22, at 4:36 p.m. EST. This is the 97th Shuttle flight and 14th for Shuttle Endeavour.
ERIC Educational Resources Information Center
Asher, Sandy
1995-01-01
Presents a script for a 1-act play about a 17-year-old girl whose mother neglects her and her alcoholic absentee father. Relates how the protagonist, Tara, becomes pregnant by a classmate who she barely knows, and plans to leave home to raise her child alone after graduating high school. (PA)
Bizot, Jean-Charles; Herpin, Alexandre; Pothion, Stéphanie; Pirot, Sylvain; Trovero, Fabrice; Ollat, Hélène
2005-07-01
The effect of a sulbutiamine chronic treatment on memory was studied in rats with a spatial delayed-non-match-to-sample (DNMTS) task in a radial maze and a two trial object recognition task. After completion of training in the DNMTS task, animals were subjected for 9 weeks to daily injections of either saline or sulbutiamine (12.5 or 25 mg/kg). Sulbutiamine did not modify memory in the DNMTS task but improved it in the object recognition task. Dizocilpine, impaired both acquisition and retention of the DNMTS task in the saline-treated group, but not in the two sulbutiamine-treated groups, suggesting that sulbutiamine may counteract the amnesia induced by a blockade of the N-methyl-D-aspartate glutamate receptors. Taken together, these results are in favor of a beneficial effect of sulbutiamine on working and episodic memory. PMID:15951087
NASA Astrophysics Data System (ADS)
Majhi, S. K.; Mukhopadhyay, A.; Ward, B. F. L.; Yost, S. A.
2014-11-01
We present a phenomenological study of the current status of the application of our approach of exact amplitude-based resummation in quantum field theory to precision QCD calculations, by realistic MC event generator methods, as needed for precision LHC physics. We discuss recent results as they relate to the interplay of the attendant IR-improved DGLAP-CS theory of one of us and the precision of exact NLO matrix-element matched parton shower MC's in the Herwig6.5 environment as determined by comparison to recent LHC experimental observations on single heavy gauge boson production and decay. The level of agreement between the new theory and the data continues to be a reason for optimism. In the spirit of completeness, we discuss as well other approaches to the same theoretical predictions that we make here from the standpoint of physical precision with an eye toward the (sub-)1% QCD ⊗ EW total theoretical precision regime for LHC physics.
NASA Astrophysics Data System (ADS)
Oh, Tae Su; Jeong, Hyun; Seo, Tae Hoon; Lee, Yong Seok; Park, Ah Hyun; Kim, Hun; Jea Lee, Kang; Suh, Eun-Kyung
2010-11-01
Using metalorganic chemical vapor deposition, a strain-free GaN layer has been successfully grown by employing a 40-nm-thick nearly lattice-matched (NLM) Al1-xInxN as an interlayer. The Al1-xInxN interlayers having an InN molar fraction of x˜0.11 and 0.13 led to crack-networking at the GaN surface due to excessive tensile strain by lattice-mismatching. In the case of the GaN layer with a NLM Al1-xInxN interlayer (x˜0.18), however, strain-free GaN structure with improved structural and optical properties was demonstrated from the results of atomic force microscopy, Raman scattering and photoluminescence. By using transmission electron microscopy (TEM), the origin on strain-free state and improved properties of the GaN layer with the NLM AlInN interlayer was investigated. Based on TEM observations, we suggest that the faulted zone-like growth mechanism on roughed AlInN surface and partial compensation of tensile thermal stress are major factors on the improved strain-free GaN film.
Visible light broadband perfect absorbers
NASA Astrophysics Data System (ADS)
Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O.
2016-03-01
The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.
Effective perfect fluids in cosmology
Ballesteros, Guillermo; Bellazzini, Brando E-mail: brando.bellazzini@pd.infn.it
2013-04-01
We describe the cosmological dynamics of perfect fluids within the framework of effective field theories. The effective action is a derivative expansion whose terms are selected by the symmetry requirements on the relevant long-distance degrees of freedom, which are identified with comoving coordinates. The perfect fluid is defined by requiring invariance of the action under internal volume-preserving diffeomorphisms and general covariance. At lowest order in derivatives, the dynamics is encoded in a single function of the entropy density that characterizes the properties of the fluid, such as the equation of state and the speed of sound. This framework allows a neat simultaneous description of fluid and metric perturbations. Longitudinal fluid perturbations are closely related to the adiabatic modes, while the transverse modes mix with vector metric perturbations as a consequence of vorticity conservation. This formalism features a large flexibility which can be of practical use for higher order perturbation theory and cosmological parameter estimation.
Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.
2013-01-01
BACKGROUND School-based social-emotional and character development (SECD) programs can influence not only SECD, but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. METHODS The longitudinal study used a matched-pair, cluster-randomized controlled design. Student-reported disaffection with learning and academic grades, and teacher ratings of academic ability and motivation were assessed for a cohort followed from grades 3 to 8. Aggregate school records were used to assess standardized test performance (for entire school, cohort, and demographic subgroups) and absenteeism (entire school). Multilevel growth-curve analyses tested program effects. RESULTS PA significantly improved growth in academic motivation and mitigated disaffection with learning. There was a positive impact of PA on absenteeism and marginally significant impact on math performance of all students. There were favorable program effects on reading for African American boys and cohort students transitioning between grades 7 and 8, and on math for girls and low-income students. CONCLUSIONS A school-based SECD program was found to influence academic outcomes among students living in low-income, urban communities. Future research should examine mechanisms by which changes in SECD influence changes in academic outcomes. PMID:24138347
Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho
2016-01-01
This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility. PMID:26978366
Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho
2016-01-01
This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility. PMID:26978366
Albinsson, John; Brorsson, Sofia; Ahlgren, Asa Rydén; Cinthio, Magnus
2014-10-01
The aim of this study was to evaluate tracking performance when an extra reference block is added to a basic block-matching method, where the two reference blocks originate from two consecutive ultrasound frames. The use of an extra reference block was evaluated for two putative benefits: (i) an increase in tracking performance while maintaining the size of the reference blocks, evaluated using in silico and phantom cine loops; (ii) a reduction in the size of the reference blocks while maintaining the tracking performance, evaluated using in vivo cine loops of the common carotid artery where the longitudinal movement of the wall was estimated. The results indicated that tracking accuracy improved (mean = 48%, p < 0.005 [in silico]; mean = 43%, p < 0.01 [phantom]), and there was a reduction in size of the reference blocks while maintaining tracking performance (mean = 19%, p < 0.01 [in vivo]). This novel method will facilitate further exploration of the longitudinal movement of the arterial wall. PMID:25130445
Generating perfect fluid spheres in general relativity
NASA Astrophysics Data System (ADS)
Boonserm, Petarpa; Visser, Matt; Weinfurtner, Silke
2005-06-01
Ever since Karl Schwarzschild’s 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star—a static spherically symmetric blob of fluid with position-independent density—the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres.
Will a perfect global model agree with perfect observations?
NASA Astrophysics Data System (ADS)
Schutgens, N.; Gryspeerdt, E.; Tsyro, S.; Weigum, N.; Partridge, D.; Goto, D.; Schulz, M.; Stier, P.
2015-12-01
Global aerosol models and observations differ strongly in their spatio-temporal sampling. Model results are typical of large gridboxes (200 by 200 km), while observations are made over much smaller areas (e.g. 10 by 10 km for MODIS, even smaller for ground sites). Model results are always available in contrast to observations that are intermittent due to orbital constraints, retrieval limitations and instrument failure/maintenance. These twin issues of temporal sampling and spatial aggregation are relevant for any observation, be it remotely sensed, or in-situ. We ask this question: will a perfect model agree with perfect observations? The short answer is: unlikely. Using two different modelling frame-works (year-long global model runs collocated with actual observations and month-long high resolution regional models runs) we show that significant errors can be introduced in a model to observation comparison due to different spatio-temporal sampling. These sampling errors are typically larger than observational errors and are of comparable size as true model errors. While the temporal sampling issue can be dealt with by properly resampling model data to observation times, the spatial aggregation issue introduces noise into the comparison. We propose and evaluate several strategies for mitigating this noise. The most succesfull strategy is further temporal averaging of the data. However, this seems to have a less benefical effect on surface in-situ observations than on remotely sensed column-integrated measurements. For instance, monthly averaged black carbon mass concentrations measured at ground sites still allow significant (~ 30%) noise into the comparison. Furthermore, flight campaign data, by its nature, are not open to long-term (monthly, yearly) averaging and allow sampling errors of 50% or more in black carbon mass concentrations. Other observables (AOT, extinction profiles, number densities, PM2.5, CCN) will also be discussed.
Breidbach, Andreas; Ulberth, Franz
2015-04-01
Aflatoxins, mycotoxins of fungi of the Aspergillus sp., pose a risk to consumer health and are, therefore, regulated by more than 100 countries. To facilitate method development and validation as well as assessment of measurement capabilities, availability of certified reference materials and proficiency testing schemes is important. For these purposes, highly accurate determinations of the aflatoxin content in the materials used are necessary. We describe here the use of two-dimensional heart-cut LC-LC in combination with exact-matching double isotope dilution mass spectrometry to determine the content of aflatoxin B1 in three materials used in a proficiency testing scheme. The serious reduction in ionization suppression afforded by the two-dimensional heart-cut LC-LC had a positive effect on the precision of the measured isotope ratios of the exact-matching double isotope dilution mass spectrometry. This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg. This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins. The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool. PMID:25015044
Towards creating the perfect electronic prescription.
Dhavle, Ajit A; Rupp, Michael T
2015-04-01
Significant strides have been made in electronic (e)-prescribing standards and software applications that have further fueled the adoption and use of e-prescribing. However, for e-prescribing to realize its full potential for improving the safety, effectiveness, and efficiency of prescription drug delivery, important work remains to be carried out. This perspective describes the ultimate goal of all e-prescribing stakeholders including prescribers and dispensing pharmacists: a clear, complete, and unambiguous e-prescription order that can be seamlessly received, processed, and fulfilled at the dispensing pharmacy without the need for additional clarification from the prescriber. We discuss the challenges to creating the perfect e-prescription by focusing on selected data segments and data fields that are available in the new e-prescription transaction as defined in the NCPDP SCRIPT Standard and suggest steps that could be taken to move the industry closer to achieving this vision. PMID:25038197
Theory and practice of ultra-perfection.
Ouangraoua, Aïda; Bergeron, Anne; Swenson, Krister M
2011-09-01
Perfection has been used as a criteria to classify rearrangement scenarios since 2004. However, there is a fundamental bias towards extant species in the original definition: ancestral species are not bound to perfection. Here we develop a new theory of perfection that takes an egalitarian view of species, and we examine the fitness of this theory on several datasets. Supplementary Material is available at www.liebertonline.com/cmb. PMID:21899427
The Perfect Principal: A Teacher's Fantasy.
ERIC Educational Resources Information Center
Webb, Diana
1985-01-01
Briefly describes the perfect principal's leadership, consciousness of human relations, charisma, visibility, high standards, positive attitude, openness, organization, consistency, and involvement in professional activities. (PGD)
Odd perfect numbers have a prime factor exceeding 10^8
NASA Astrophysics Data System (ADS)
Goto, Takeshi; Ohno, Yasuo
2008-09-01
Jenkins in 2003 showed that every odd perfect number is divisible by a prime exceeding 10^7 . Using the properties of cyclotomic polynomials, we improve this result to show that every perfect number is divisible by a prime exceeding 10^8 .
Perfect Actions and Operators for Lattice QCD
NASA Astrophysics Data System (ADS)
Wiese, Uwe-Jens
1996-05-01
Wilson's renormalization group implies that lattice actions located on a renormalized trajectory emanating from a fixed point represent perfect discretizations of continuum physics. With a perfect action the spectrum of a lattice theory is identical with the one of the continuum theory even at finite lattice spacing. Similarly, perfect operators yield cut-off independent matrix elements. Hence, continuum QCD can in principle be reconstructed from a lattice with finite spacing. In practice it is difficult to construct perfect actions and perfect operators explicitly. Here perturbation theory is used to derive perfect actions for quarks and gluons by performing a block renormalization group transformation directly from the continuum. The renormalized trajectory for free massive quarks is identified and a parameter in the renormalization group transformation is tuned such that for 1-d configurations the perfect action reduces to the nearest neighbor Wilson fermion action. Then the 4-d perfect action turns out to be extremely local as well, which is vital for numerical simulations. The fixed point action for free gluons is also obtained by blocking from the continuum. For 2-d configurations it reduces to the standard plaquette action, and for 4-d configurations it is still very local. With interactions between quarks and gluons switched on the perfect quark-gluon and 3-gluon vertex functions are computed analytically. In particular, a perfect clover term can be extracted from the quark-gluon vertex. The perturbatively perfect action is directly applicable to heavy quark physics. The construction of a perfect QCD action for light quarks should include nonperturbative effects, which is possible using numerical methods. Classically perfect quark and gluon fields are constructed as well. They allow to interpolate the continuum fields from the lattice data. In this way one can obtain information about space-time regions between lattice points. The classically perfect fields
Semiperfect and Integer-Perfect Numbers.
ERIC Educational Resources Information Center
Costello, Patrick
1991-01-01
The number theory concepts of perfect, deficient, and abundant numbers are subdivided and then utilized to discuss propositions concerning semiperfect, weird, and integer-perfect numbers. Conjectures about relationships among these latter numbers are suggested as avenues for further investigation. (JJK)
Hybrid Schema Matching for Deep Web
NASA Astrophysics Data System (ADS)
Chen, Kerui; Zuo, Wanli; He, Fengling; Chen, Yongheng
Schema matching is the process of identifying semantic mappings, or correspondences, between two or more schemas. Schema matching is a first step and critical part of data integration. For schema matching of deep web, most researches only interested in query interface, while rarely pay attention to abundant schema information contained in query result pages. This paper proposed a mixed schema matching technique, which combines attributes that appeared in query structures and query results of different data sources, and mines the matched schemas inside. Experimental results prove the effectiveness of this method for improving the accuracy of schema matching.
ERIC Educational Resources Information Center
Bavarian, Niloofar; Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.
2013-01-01
Background: School-based social-emotional and character development (SECD) programs can influence not only SECD but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. Methods: The longitudinal study used a matched-pair, cluster-randomized…
Computation of Thermally Perfect Compressible Flow Properties
NASA Technical Reports Server (NTRS)
Witte, David W.; Tatum, Kenneth E.; Williams, S. Blake
1996-01-01
A set of compressible flow relations for a thermally perfect, calorically imperfect gas are derived for a value of c(sub p) (specific heat at constant pressure) expressed as a polynomial function of temperature and developed into a computer program, referred to as the Thermally Perfect Gas (TPG) code. The code is available free from the NASA Langley Software Server at URL http://www.larc.nasa.gov/LSS. The code produces tables of compressible flow properties similar to those found in NACA Report 1135. Unlike the NACA Report 1135 tables which are valid only in the calorically perfect temperature regime the TPG code results are also valid in the thermally perfect, calorically imperfect temperature regime, giving the TPG code a considerably larger range of temperature application. Accuracy of the TPG code in the calorically perfect and in the thermally perfect, calorically imperfect temperature regimes are verified by comparisons with the methods of NACA Report 1135. The advantages of the TPG code compared to the thermally perfect, calorically imperfect method of NACA Report 1135 are its applicability to any type of gas (monatomic, diatomic, triatomic, or polyatomic) or any specified mixture of gases, ease-of-use, and tabulated results.
Crystal structure of a perfect carbyne
Belenkov, E. A. Mavrinsky, V. V.
2008-01-15
The crystal structure of a perfect carbyne is calculated by the molecular mechanics methods. It is established that the carbyne crystals should consist of polycumulene chains arranged in hexagonal bundles. The unit cell of the perfect carbyne crystal is trigonal and contains one carbon atom. The unit cell parameters are as follows: a = b = c = 0.3580 nm, {alpha} = {beta} = {gamma} = 118.5{sup o}, and space group P3m1. The perfect carbyne single crystals have a stable structure at room temperature if the length of their constituent chains is larger than 500 nm.
Complexity matching in neural networks
NASA Astrophysics Data System (ADS)
Usefie Mafahim, Javad; Lambert, David; Zare, Marzieh; Grigolini, Paolo
2015-01-01
In the wide literature on the brain and neural network dynamics the notion of criticality is being adopted by an increasing number of researchers, with no general agreement on its theoretical definition, but with consensus that criticality makes the brain very sensitive to external stimuli. We adopt the complexity matching principle that the maximal efficiency of communication between two complex networks is realized when both of them are at criticality. We use this principle to establish the value of the neuronal interaction strength at which criticality occurs, yielding a perfect agreement with the adoption of temporal complexity as criticality indicator. The emergence of a scale-free distribution of avalanche size is proved to occur in a supercritical regime. We use an integrate-and-fire model where the randomness of each neuron is only due to the random choice of a new initial condition after firing. The new model shares with that proposed by Izikevich the property of generating excessive periodicity, and with it the annihilation of temporal complexity at supercritical values of the interaction strength. We find that the concentration of inhibitory links can be used as a control parameter and that for a sufficiently large concentration of inhibitory links criticality is recovered again. Finally, we show that the response of a neural network at criticality to a harmonic stimulus is very weak, in accordance with the complexity matching principle.
Skyline based terrain matching
NASA Technical Reports Server (NTRS)
Page, Lance A.
1990-01-01
Skyline-based terrain matching, a new method for locating the vantage point of stereo camera or laser range-finding measurements on a global map previously prepared by satellite or aerial mapping is described. The orientation of the vantage is assumed known, but its translational parameters are determined by the algorithm. Skylines, or occluding contours, can be extracted from the sensory measurements taken by an autonomous vehicle. They can also be modeled from the global map, given a vantage estimate from which to start. The two sets of skylines, represented in cylindrical coordinates about either the true or the estimated vantage, are employed as 'features' or reference objects common to both sources of information. The terrain matching problem is formulated in terms of finding a translation between the respective representations of the skylines, by approximating the two sets of skylines as identical features (curves) on the actual terrain. The search for this translation is based on selecting the longest of the minimum-distance vectors between corresponding curves from the two sets of skylines. In successive iterations of the algorithm, the approximation that the two sets of curves are identical becomes more accurate, and the vantage estimate continues to improve. The algorithm was implemented and evaluated on a simulated terrain. Illustrations and examples are included.
Study on matching map for the absorber filled by metallic magnetic particles
NASA Astrophysics Data System (ADS)
Wang, Tao; Xu, Fei; Tang, Liyun; Qiao, Liang; Li, Fashen
2014-11-01
A map displaying the matching characteristics and absorption performance for the metallic carbonyl iron composite in microwave frequency band is developed based on the origin of absorption peaks. In this map, the dependence of matching frequency fm on absorber thickness, input impendence, and absorption peak value is achieved simultaneously from the complex permeability and permittivity spectra without any approximation. From this map, the perfect matching frequency fpm and perfect matching thickness tpm at input impendence Z = 1 can be directly searched. Moreover, the required absorber thickness and the reflection loss value at any expected frequency where the absorption peak locates can be directly observed.
Developments in Coherent Perfect Polarization Rotation
NASA Astrophysics Data System (ADS)
Crescimanno, Michael; Andrews, James; Zhou, Chaunhong; Baker, Michael
2015-05-01
Coherent Perfect Polarization Rotation (CPR) is a useful technique akin to Coherent Perfect Absorption (CPA, also known as the anti-laser) but that results in very high efficiency optical mode conversion. We describe the analysis of recent experimental data from our CPR testbed, the use of CPR in miniaturizing optical isolators and CPR phenomena in non-linear optics. Work supported by the N.S.F. under Grant No. ECCS-1360725.
ERIC Educational Resources Information Center
Ferrara, Steve; Perie, Marianne; Johnson, Eugene
2008-01-01
Psychometricians continue to introduce new approaches to setting cut scores for educational assessments in an attempt to improve on current methods. In this paper we describe the Item-Descriptor (ID) Matching method, a method based on IRT item mapping. In ID Matching, test content area experts match items (i.e., their judgments about the knowledge…
Matching a Distribution by Matching Quantiles Estimation
Sgouropoulos, Nikolaos; Yao, Qiwei; Yastremiz, Claudia
2015-01-01
Motivated by the problem of selecting representative portfolios for backtesting counterparty credit risks, we propose a matching quantiles estimation (MQE) method for matching a target distribution by that of a linear combination of a set of random variables. An iterative procedure based on the ordinary least-squares estimation (OLS) is proposed to compute MQE. MQE can be easily modified by adding a LASSO penalty term if a sparse representation is desired, or by restricting the matching within certain range of quantiles to match a part of the target distribution. The convergence of the algorithm and the asymptotic properties of the estimation, both with or without LASSO, are established. A measure and an associated statistical test are proposed to assess the goodness-of-match. The finite sample properties are illustrated by simulation. An application in selecting a counterparty representative portfolio with a real dataset is reported. The proposed MQE also finds applications in portfolio tracking, which demonstrates the usefulness of combining MQE with LASSO. PMID:26692592
Morphology and structural perfection of shaped sapphire
NASA Astrophysics Data System (ADS)
Dobrovinskaya, E. R.; Litvinov, L. A.; Pishchik, V. V.
1980-09-01
This paper is concerned with an investigation of the characteristic features in the structural perfection of sapphire crystals grown by the Stepanov method. It was shown that the formation of the mosaic grains was considerably dependent on the growth rate. When growing tubular shaped crystals the defect density is relatively insensitive to the growth rate. The structural perfection of shaped sapphire depends on the ratio of the emitting outer surface area to the volume of the crystal. Growth of sapphire shapes occurs by addition of separate atoms and also by the joining of the complexes first formed in the melt before the crystallization front. Upon incoherent crystal twinning, formation of dislocations and boundaries with small angle misorientations takes place. The observed features in the morphology and the structural perfection of shaped sapphire obtained by the Stepanov technique are caused by the considerable differences in crystallization conditions characteristic of this method. These differences result in a change in the growth mechanism.
Overlapped optics induced perfect coherent effects.
Li, Jian Jie; Zang, Xiao Fei; Mao, Jun Fa; Tang, Min; Zhu, Yi Ming; Zhuang, Song Lin
2013-01-01
For traditional coherent effects, two separated identical point sources can be interfered with each other only when the optical path difference is integer number of wavelengths, leading to alternate dark and bright fringes for different optical path difference. For hundreds of years, such a perfect coherent condition seems insurmountable. However, in this paper, based on transformation optics, two separated in-phase identical point sources can induce perfect interference with each other without satisfying the traditional coherent condition. This shifting illusion media is realized by inductor-capacitor transmission line network. Theoretical analysis, numerical simulations and experimental results are performed to confirm such a kind of perfect coherent effect and it is found that the total radiation power of multiple elements system can be greatly enhanced. Our investigation may be applicable to National Ignition Facility (NIF), Inertial Confined Fusion (ICF) of China, LED lighting technology, terahertz communication, and so on. PMID:24356577
NASA Astrophysics Data System (ADS)
Komolibus, Katarzyna; Scofield, Adam C.; Gradkowski, Kamil; Ochalski, Tomasz J.; Kim, Hyunseok; Huffaker, Diana L.; Huyet, Guillaume
2016-02-01
Optical properties of GaAs/InGaAs/GaAs nanopillars (NPs) grown on GaAs(111)B were investigated. Employment of a mask-etching technique allowed for an accurate control over the geometry of NP arrays in terms of both their diameter and separation. This work describes both the steady-state and time-resolved photoluminescence of these structures as a function of the ensemble geometry, composition of the insert, and various shell compounds. The effects of the NP geometry on a parasitic radiative recombination channel, originating from an overgrown lateral sidewall layer, are discussed. Optical characterization reveals a profound influence of the core-shell lattice mismatch on the carrier lifetime and emission quenching at room temperature. When the lattice-matching conditions are satisfied, an efficient emission from the NP arrays at room temperature and below the band-gap of silicon is observed, clearly highlighting their potential application as emitters in optical interconnects integrated with silicon platforms.
Near-perfect diffraction grating rhomb
Wantuck, Paul J.
1990-01-01
A near-perfect grating rhomb enables an output beam to be diffracted to an angle offset from the input beam. The correcting grating is tipped relative to the dispersing grating to provide the offset angle. The correcting grating is further provided with a groove spacing which differs from the dispersing grating groove space by an amount effective to substantially remove angular dispersion in the output beam. A near-perfect grating rhomb has the capability for selective placement in a FEL to suppress sideband instabilities arising from the FEL.
Coherent perfect absorber based on metamaterials
NASA Astrophysics Data System (ADS)
Nie, Guangyu; Shi, Quanchao; Zhu, Zheng; Shi, Jinhui
2014-11-01
We demonstrate selective coherent perfect absorption based on interaction between bilayered asymmetrically split rings (ASRs) metamaterials and a standing wave formed by two coherent counter propagating beams. The selective coherent perfect absorbers with high absorption have been achieved depending on the phase difference between two coherent beams. The selective coherent control absorbers can be well designed by changing the thickness of the dielectric layer and the asymmetry of the ASRs. The coherently controlled metamaterials provide an opportunity to realize selective multiband absorption and ultrafast information processing.
Generation of perfect vectorial vortex beams.
Li, Peng; Zhang, Yi; Liu, Sheng; Ma, Chaojie; Han, Lei; Cheng, Huachao; Zhao, Jianlin
2016-05-15
We propose the concept of perfect vectorial vortex beams (VVBs), which not merely have intensity profile independent of the polarization order and the topological charge of spiral phase, but also have stable intensity profile and state of polarization (SoP) upon propagation. Utilizing a Sagnac interferometer, we approximately generate perfect VVBs with locally linear and elliptical polarizations, and demonstrate that such beams can keep their intensity profile and SoP at a certain propagation distance. These proposed VVBs can be expanded to encode information and quantum cryptography, as well as to enrich the conversion of spin and orbital angular momenta. PMID:27176963
Selective coherent perfect absorption in metamaterials
Nie, Guangyu; Shi, Quanchao; Zhu, Zheng; Shi, Jinhui
2014-11-17
We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency.
Electromagnetic Detection of a Perfect Invisibility Cloak
Zhang Baile; Wu, Bae-Ian
2009-12-11
A perfect invisibility cloak is commonly believed to be undetectable from electromagnetic (EM) detection because it is equivalent to a curved but empty EM space created from coordinate transformation. Based on the intrinsic asymmetry of coordinate transformation applied to motions of photons and charges, we propose a method to detect this curved EM space by shooting a fast-moving charged particle through it. A broadband radiation generated in this process makes a cloak visible. Our method is the only known EM mechanism so far to detect an ideal perfect cloak (curved EM space) within its working band.
Block Matching for Object Tracking
Gyaourova, A; Kamath, C; Cheung, S
2003-10-13
Models which describe road traffic patterns can be helpful in detection and/or prevention of uncommon and dangerous situations. Such models can be built by the use of motion detection algorithms applied to video data. Block matching is a standard technique for encoding motion in video compression algorithms. We explored the capabilities of the block matching algorithm when applied for object tracking. The goal of our experiments is two-fold: (1) to explore the abilities of the block matching algorithm on low resolution and low frame rate video and (2) to improve the motion detection performance by the use of different search techniques during the process of block matching. Our experiments showed that the block matching algorithm yields good object tracking results and can be used with high success on low resolution and low frame rate video data. We observed that different searching methods have small effect on the final results. In addition, we proposed a technique based on frame history, which successfully overcame false motion caused by small camera movements.
NASA Astrophysics Data System (ADS)
Murakami, Shuichi; Takahashi, Ryuji; Tretiakov, O. A.; Abanov, Ar; Sinova, Jairo
2011-12-01
Topological insulators have gapless edge/surface states with novel transport properties. Among these, there are two classes of perfectly conducting channels which are free from backscattering: the edge states of two-dimensional topological insulators and the one-dimensional states localized on dislocations of certain three-dimensional topological insulators. We show how these novel states affect thermoelectric properties of the systems and discuss possibilities to improve the thermoelectric figure of merit using these materials with perfectly conducting channels.
Grötzinger, Stefan W.; Alam, Intikhab; Ba Alawi, Wail; Bajic, Vladimir B.; Stingl, Ulrich; Eppinger, Jörg
2014-01-01
Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile's genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the Integrated Data Warehouse of Microbial Genomes (INDIGO) data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes) may translate into false positives when searching for specific functions. The Profile and Pattern Matching (PPM) strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO)-terms (which represent enzyme function profiles) and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern). The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2577 enzyme commission (E.C.) numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from six different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter) and PROSITE IDs (pattern filter). Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits) are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns) are present. Scripts for annotation, as well as for the PPM algorithm, are available
Maple Explorations, Perfect Numbers, and Mersenne Primes
ERIC Educational Resources Information Center
Ghusayni, B.
2005-01-01
Some examples from different areas of mathematics are explored to give a working knowledge of the computer algebra system Maple. Perfect numbers and Mersenne primes, which have fascinated people for a very long time and continue to do so, are studied using Maple and some questions are posed that still await answers.
Children Prefer Certain Individuals over Perfect Duplicates
ERIC Educational Resources Information Center
Hood, Bruce M.; Bloom, Paul.
2008-01-01
Adults value certain unique individuals--such as artwork, sentimental possessions, and memorabilia--more than perfect duplicates. Here we explore the origins of this bias in young children, by using a conjurer's illusion where we appear to produce identical copies of real-world objects. In Study 1, young children were less likely to accept an…
Le Perfectionnement en Phonetique (Perfecting Phonetics)
ERIC Educational Resources Information Center
Laroche-Bouvy, Danielle
1975-01-01
This article describes the programs of the Institut d'Etudes Linguistiques et Phonetiques, located in Paris. The program focuses on perfecting the students' phonetic production of French. Both curriculum and teaching methods are described, as well as a course in phonetics for future teachers of French. (Text is in French.) (CLK)
Mechanical Energy Changes in Perfectly Inelastic Collisions
ERIC Educational Resources Information Center
Mungan, Carl E.
2013-01-01
Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)
A Reappraisal of the Nobody's Perfect Program
ERIC Educational Resources Information Center
Kennett, Deborah J.; Chislett, Gail; Olver, Ashley L. S.
2012-01-01
Nobody's Perfect Program (NP), involving 46 participants, was conducted from the spring of 2007 to the fall of 2009 in Peterborough, Canada. Prior to the program, parents completed demographic information, along with self-report measures assessing learned resourcefulness, the types of interactions with their children, parent resourcefulness,…
The Present Perfect in World Englishes
ERIC Educational Resources Information Center
Yao, Xinyue; Collins, Peter
2012-01-01
This paper reports on a comprehensive corpus-based study of regional and stylistic variation in the distribution of the English present perfect. The data represents ten English varieties of both the Inner Circle and Outer Circle, covering four major text types: conversation, news reportage, academic and fictional writing. The results are discussed…
Ding, Xiong; Nie, Kai; Shi, Lei; Zhang, Yong; Guan, Li; Zhang, Dan
2014-01-01
Rapid detection of human enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) is important in the early phase of hand-foot-and-mouth disease (HFMD). In this study, we developed and evaluated a novel reverse transcription–isothermal multiple-self-matching-initiated amplification (RT-IMSA) assay for the rapid detection of EV71 and CVA16 by use of reverse transcriptase, together with a strand displacement DNA polymerase. Real-time RT-IMSA assays using a turbidimeter and visual RT-IMSA assays to detect EV71 and CVA16 were established and completed in 1 h, and the reported corresponding real-time reverse transcription–loop-mediated isothermal amplification (RT-LAMP) assays targeting the same regions of the VP1 gene were adopted as parallel tests. Through testing VP1 RNAs transcribed in vitro, the real-time RT-IMSA assays exhibited better linearity of quantification, with R2 values of 0.952 (for EV71) and 0.967 (for CVA16), than the real-time RT-LAMP assays, which had R2 values of 0.803 (for EV71) and 0.904 (for CVA16). Additionally, the detection limits of the real-time RT-IMSA assays (approximately 937 for EV71 and 67 for CVA16 copies/reaction) were higher than those of real-time RT-LAMP assays (approximately 3,266 for EV71 and 430 for CVA16 copies/reaction), and similar results were observed in the visual RT-IMSA assays. The new approaches also possess high specificities for the corresponding targets, with no cross-reactivity observed. In clinical assessment, compared to commercial reverse transcription-quantitative PCR (qRT-PCR) kits, the diagnostic sensitivities of the real-time RT-IMSA assays (96.4% for EV71 and 94.6% for CVA16) were higher than those of the real-time RT-LAMP assays (91.1% for EV71 and 90.8% for CVA16). The visual RT-IMSA assays also exhibited the same results. In conclusion, this proof-of-concept study suggests that the novel RT-IMSA assay is superior to the RT-LAMP assay in terms of detection limit and has the potential to rapidly detect EV71
School Social Work Consultation Models and Response to Intervention: A Perfect Match
ERIC Educational Resources Information Center
Sabatino, Christine Anlauf
2009-01-01
The 2004 amendments to the Individuals with Disabilities Education Act introduced the concept of Response to Intervention (RTI). In part, this is an educational prevention approach to maximize student academic achievement and minimize behaviors that interfere with school success. It consists of assessment and intervention practices on multiple…
Inter-Sentential Anaphora and Coherence Relations in Discourse: A Perfect Match
ERIC Educational Resources Information Center
Cornish, Francis
2009-01-01
Hobbs [Hobbs, J.R., 1979. "Coherence and coreference." "Cognitive Science" 3, 67-90] claims that the interpretation of inter-sentential anaphors "falls out" as a "by-product" of using a particular coherence relation to integrate two discourse units. The article argues that this is only partly true. Taking the reader's perspective, I suggest that…
Text-Based Synchronous E-Learning and Dyslexia: Not Necessarily the Perfect Match!
ERIC Educational Resources Information Center
Woodfine, B. P.; Nunes, M. Baptista; Wright, D. J.
2008-01-01
The introduction, in the United Kingdom, of the Special Education Needs and Disabilities Act (SENDA) published and approved in 2001, has removed the exemptions given to educational institutions by the Disabilities Discrimination Act (DDA) of 1995. This applies to learning web sites and materials that must now undergo "reasonable adjustments", in…
Dr Marvin Adams
2002-03-01
OAK 270 - The DOE Matching Grant Program provided $50,000.00 to the Dept of N.E. at TAMU, matching a gift of $50,000.00 from TXU Electric. The $100,000.00 total was spent on scholarships, departmental labs, and computing network.
NASA Astrophysics Data System (ADS)
Liang, Zhongjie T.
1992-05-01
The generic imaging matching system (GIMS) provides an optimal systematic solution to any problem of color image processing in printing and publishing that can be classified as or modeled to the generic image matching problem defined. Typical GIMS systems/processes include color matching from different output devices, color conversion, color correction, device calibration, colorimetric scanner, colorimetric printer, colorimetric color reproduction, and image interpolation from scattered data. GIMS makes color matching easy for the user and maximizes operational flexibility allowing the user to obtain the degree of match wanted while providing the capability to achieve the best balance with respect to the human perception of color, color fidelity, and preservation of image information and color contrast. Instead of controlling coefficients in a transformation formula, GIMS controls the mapping directly in a standard device-independent color space, so that color can be matched, conceptually, to the highest possible accuracy. An optimization algorithm called modified vector shading was developed to minimize the matching error and to perform a 'near-neighborhood' gamut compression. An automatic error correction algorithm with a multidirection searching procedure using correlated re-initialization was developed to avoid local minimum failures. Once the mapping for color matching is generated, it can be utilized by a multidimensional linear interpolator with a small look-up-table (LUT) implemented by either software, a hardware interpolator or a digital-signal-processor.
NASA Astrophysics Data System (ADS)
Haberzettl, T.; Kasper, T.; St-Onge, G.; Behling, H.; Daut, G.; Doberschütz, S.; Kirleis, W.; Mäusbacher, R.; Nowaczyk, N.
2010-12-01
were chosen for age-depth modeling and a linear interpolation was applied. Subsequently, inclination, declination and intensity were compared to the CALS3k.3 model also showing an excellent match from ~1350 cal BP to the present. Although, the age-depth models of both lakes are conservative, comparisons of paleomagnetic data with geomagnetic spherical harmonic models support this approach. This leads to the conclusion that the presented chronologies are suited for further paleoenvironmental investigations. This is important as both areas lack well-dated records. On the other hand, our data also support the validity of the CALS-models for the past ~4000 and ~1350 cal BP on the Tibetan Plateau and Indonesia, where paleomagnetic data are very scarce.
ACE Inhibition and Endothelial Function: Main Findings of PERFECT, a Sub-Study of the EUROPA Trial
Remme, W. J.; Lüscher, T. F.; Fox, K. M.; Bertrand, M.; Ferrari, R.; Simoons, M. L.; Grobbee, D. E.
2007-01-01
Background ACE inhibition results in secondary prevention of coronary artery disease (CAD) through different mechanisms including improvement of endothelial dysfunction. The Perindopril-Function of the Endothelium in Coronary artery disease Trial (PERFECT) evaluated whether long-term administration of perindopril improves endothelial dysfunction. Methods PERFECT is a 3-year double blind randomised placebo controlled trial to determine the effect of perindopril 8 mg once daily on brachial artery endothelial function in patients with stable CAD without clinical heart failure. Endothelial function in response to ischaemia was assessed using ultrasound. Primary endpoint was difference in flow-mediated vasodilatation (FMD) assessed at 36 months. Results In 20 centers, 333 patients randomly received perindopril or matching placebo. Ischemia-induced FMD was 2.7% (SD 2.6). In the perindopril group FMD went from 2.6% at baseline to 3.3% at 36 months and in the placebo group from 2.8 to 3.0%. Change in FMD after 36 month treatment was 0.55% (95% confidence interval −0.36, 1.47; p = 0.23) higher in perindopril than in placebo group. The rate of change in FMD per 6 months was 0.14% (SE 0.05, p = 0.02) in perindopril and 0.02% (SE 0.05, p = 0.74) in placebo group (0.12% difference in rate of change p = 0.07). Conclusion Perindopril resulted in a modest, albeit not statistically significant, improvement in FMD. PMID:17657599
Visualizing underwater acoustic matched-field processing
NASA Astrophysics Data System (ADS)
Rosenblum, Lawrence; Kamgar-Parsi, Behzad; Karahalios, Margarida; Heitmeyer, Richard
1991-06-01
Matched-field processing is a new technique for processing ocean acoustic data measured by an array of hydrophones. It produces estimates of the location of sources of acoustic energy. This method differs from source localization techniques in other disciplines in that it uses the complex underwater acoustic environment to improve the accuracy of the source localization. An unexplored problem in matched-field processing has been to separate multiple sources within a matched-field ambiguity function. Underwater acoustic processing is one of many disciplines where a synthesis of computer graphics and image processing is producing new insight. The benefits of different volume visualization algorithms for matched-field display are discussed. The authors show how this led to a template matching scheme for identifying a source within the matched-field ambiguity function that can help move toward an automated source localization process.
NASA Astrophysics Data System (ADS)
Janthong, Bancha; Hongsingthong, Aswin; Moriya, Yuki; Sichanugrist, Porponth; Wronski, Christophe R.; Konagai, Makoto
2012-10-01
We prepared and applied a-SiOx thin films to hydrogenated microcrystalline silicon solar cells (µc-Si:H) as a front antireflection layer (FAL) in order to reduce optical reflection loss. By inserting the optimized SiOx FAL with a refractive index of ˜1.75 into the glass/ZnO interface a relative increase in short-circuit current density (Jsc) by 5% could be obtained which corresponded to an improved spectral response in the 550-950 nm wavelength regions. In addition, this optimized FAL did not deteriorate the properties of the ZnO layer because no significant changes in open-circuit voltage (Voc) and fill factor (FF) were observed. As a result, the cell with an efficiency of as high as 8.28% (Voc=0.495 V, Jsc=25.09 mA/cm2, FF=0.667) could be obtained.
Matching conditions of single layer absorber with sendust flaky-filler composite
NASA Astrophysics Data System (ADS)
Qiao, Liang; Li, Xiling; Wang, Tao; Tang, Liyun; Li, Fashen
2015-11-01
This paper presents a model of interface reflection interference in order to determine matching frequency and thickness with minimum reflection loss. It is found that a proper combination of the front-face reflection and back-face reflection is necessary to produce perfect matching, which leads to global minimum reflection loss. The calculated amplitude differences of the front-face reflection and back-face reflection from the derived formula agree well with the intensity variation of the microwave matching absorbing peak.
Structured Metal Film as Perfect Absorber
NASA Astrophysics Data System (ADS)
Xiong, Xiang; Jiang, Shang-Chi; Peng, Ru-Wen; Wang, Mu
2014-03-01
With standing U-shaped resonators, fish-spear-like resonator has been designed for the first time as the building block to assemble perfect absorbers. The samples have been fabricated with two-photon polymerization process and FTIR measurement results support the effectiveness of the perfect absorber design. In such a structure the polarization-dependent resonance occurs between the tines of the spears instead of the conventional design where the resonance occurs between the metallic layers separated by a dielectric interlayer. The incident light neither transmits nor reflects back which results in unit absorbance. The power of light is trapped between the tines of spears and finally be absorbed. The whole structure is covered with a continuous metallic layer with good thermo-conductance, which provides an excellent approach to deal with heat dissipation, is enlightening in exploring metamaterial absorbers.
Nonminimal coupling of perfect fluids to curvature
Bertolami, Orfeu; Lobo, Francisco S. N.; Paramos, Jorge
2008-09-15
In this work, we consider different forms of relativistic perfect fluid Lagrangian densities that yield the same gravitational field equations in general relativity (GR). A particularly intriguing example is the case with couplings of the form [1+f{sub 2}(R)]L{sub m}, where R is the scalar curvature, which induces an extra force that depends on the form of the Lagrangian density. It has been found that, considering the Lagrangian density L{sub m}=p, where p is the pressure, the extra-force vanishes. We argue that this is not the unique choice for the matter Lagrangian density, and that more natural forms for L{sub m} do not imply the vanishing of the extra force. Particular attention is paid to the impact on the classical equivalence between different Lagrangian descriptions of a perfect fluid.
The perfect machine. Building the Palomar telescope.
NASA Astrophysics Data System (ADS)
Florence, R.
The author's chronicle of the conception of the great 200-inch Palomar telescope is an inspiring account of the birth of big science and of America at its can-do apex. Countless scientists, engineers, administrators, and workmen - from Edwin Hubble, John D. Rockefeller, Elihu Root, and Andrew Carnegie, to unemployed laborers - come alive in this story of two decades of effort to create "the perfect machine".
Fast image matching algorithm based on projection characteristics
NASA Astrophysics Data System (ADS)
Zhou, Lijuan; Yue, Xiaobo; Zhou, Lijun
2011-06-01
Based on analyzing the traditional template matching algorithm, this paper identified the key factors restricting the speed of matching and put forward a brand new fast matching algorithm based on projection. Projecting the grayscale image, this algorithm converts the two-dimensional information of the image into one-dimensional one, and then matches and identifies through one-dimensional correlation, meanwhile, because of normalization has been done, when the image brightness or signal amplitude increasing in proportion, it could also perform correct matching. Experimental results show that the projection characteristics based image registration method proposed in this article could greatly improve the matching speed, which ensuring the matching accuracy as well.
Tsoukalas, L.
2002-12-31
Funding used to support a portion of the Nuclear Engineering Educational Activities. Upgrade of teaching labs, student support to attend professional conferences, salary support for graduate students. The US Department of Energy (DOE) has funded Purdue University School of Nuclear Engineering during the period of five academic years covered in this report starting in the academic year 1996-97 and ending in the academic year 2000-2001. The total amount of funding for the grant received from DOE is $416K. In the 1990's, Nuclear Engineering Education in the US experienced a significant slow down. Student enrollment, research support, number of degrees at all levels (BS, MS, and PhD), number of accredited programs, University Research and Training Reactors, all went through a decline to alarmingly low levels. Several departments closed down, while some were amalgamated with other academic units (Mechanical Engineering, Chemical Engineering, etc). The School of Nuclear Engineering at Purdue University faced a major challenge when in the mid 90's our total undergraduate enrollment for the Sophomore, Junior and Senior Years dropped in the low 30's. The DOE Matching Grant program greatly strengthened Purdue's commitment to the Nuclear Engineering discipline and has helped to dramatically improve our undergraduate and graduate enrollment, attract new faculty and raise the School of Nuclear Engineering status within the University and in the National scene (our undergraduate enrollment has actually tripled and stands at an all time high of over 90 students; total enrollment currently exceeds 110 students). In this final technical report we outline and summarize how the grant was expended at Purdue University.
The molecular matching problem
NASA Technical Reports Server (NTRS)
Kincaid, Rex K.
1993-01-01
Molecular chemistry contains many difficult optimization problems that have begun to attract the attention of optimizers in the Operations Research community. Problems including protein folding, molecular conformation, molecular similarity, and molecular matching have been addressed. Minimum energy conformations for simple molecular structures such as water clusters, Lennard-Jones microclusters, and short polypeptides have dominated the literature to date. However, a variety of interesting problems exist and we focus here on a molecular structure matching (MSM) problem.
A note on perfect scalar fields
NASA Astrophysics Data System (ADS)
Unnikrishnan, Sanil; Sriramkumar, L.
2010-05-01
We derive a condition on the Lagrangian density describing a generic, single, noncanonical scalar field, by demanding that the intrinsic, nonadiabatic pressure perturbation associated with the scalar field vanishes identically. Based on the analogy with perfect fluids, we refer to such fields as perfect scalar fields. It is common knowledge that models that depend only on the kinetic energy of the scalar field (often referred to as pure kinetic models) possess no nonadiabatic pressure perturbation. While we are able to construct models that seemingly depend on the scalar field and also do not contain any nonadiabatic pressure perturbation, we find that all such models that we construct allow a redefinition of the field under which they reduce to pure kinetic models. We show that, if a perfect scalar field drives inflation, then, in such situations, the first slow roll parameter will always be a monotonically decreasing function of time. We point out that this behavior implies that these scalar fields cannot lead to features in the inflationary, scalar perturbation spectrum.
A note on perfect scalar fields
Unnikrishnan, Sanil; Sriramkumar, L.
2010-05-15
We derive a condition on the Lagrangian density describing a generic, single, noncanonical scalar field, by demanding that the intrinsic, nonadiabatic pressure perturbation associated with the scalar field vanishes identically. Based on the analogy with perfect fluids, we refer to such fields as perfect scalar fields. It is common knowledge that models that depend only on the kinetic energy of the scalar field (often referred to as pure kinetic models) possess no nonadiabatic pressure perturbation. While we are able to construct models that seemingly depend on the scalar field and also do not contain any nonadiabatic pressure perturbation, we find that all such models that we construct allow a redefinition of the field under which they reduce to pure kinetic models. We show that, if a perfect scalar field drives inflation, then, in such situations, the first slow roll parameter will always be a monotonically decreasing function of time. We point out that this behavior implies that these scalar fields cannot lead to features in the inflationary, scalar perturbation spectrum.
Optimal Feedback Controlled Assembly of Perfect Crystals.
Tang, Xun; Rupp, Bradley; Yang, Yuguang; Edwards, Tara D; Grover, Martha A; Bevan, Michael A
2016-07-26
Perfectly ordered states are targets in diverse molecular to microscale systems involving, for example, atomic clusters, protein folding, protein crystallization, nanoparticle superlattices, and colloidal crystals. However, there is no obvious approach to control the assembly of perfectly ordered global free energy minimum structures; near-equilibrium assembly is impractically slow, and faster out-of-equilibrium processes generally terminate in defective states. Here, we demonstrate the rapid and robust assembly of perfect crystals by navigating kinetic bottlenecks using closed-loop control of electric field mediated crystallization of colloidal particles. An optimal policy is computed with dynamic programming using a reaction coordinate based dynamic model. By tracking real-time stochastic particle configurations and adjusting applied fields via feedback, the evolution of unassembled particles is guided through polycrystalline states into single domain crystals. This approach to controlling the assembly of a target structure is based on general principles that make it applicable to a broad range of processes from nano- to microscales (where tuning a global thermodynamic variable yields temporal control over thermal sampling of different states via their relative free energies). PMID:27387146
Solute drag on perfect and extended dislocations
NASA Astrophysics Data System (ADS)
Sills, R. B.; Cai, W.
2016-04-01
The drag force exerted on a moving dislocation by a field of mobile solutes is studied in the steady state. The drag force is numerically calculated as a function of the dislocation velocity for both perfect and extended dislocations. The sensitivity of the non-dimensionalized force-velocity curve to the various controlling parameters is assessed, and an approximate analytical force-velocity expression is given. A non-dimensional parameter S characterizing the strength of the solute-dislocation interaction, the background solute fraction ?, and the dislocation character angle ?, are found to have the strongest influence on the force-velocity curve. Within the model considered here, a perfect screw dislocation experiences no solute drag, but an extended screw dislocation experiences a non-zero drag force that is about 10 to 30% of the drag on an extended edge dislocation. The solutes can change the spacing between the Shockley partials in both stationary and moving extended dislocations, even when the stacking fault energy remains unaltered. Under certain conditions, the solutes destabilize an extended dislocation by either collapsing it into a perfect dislocation or causing the partials to separate unboundedly. It is proposed that the latter instability may lead to the formation of large faulted areas and deformation twins in low stacking fault energy materials containing solutes, consistent with experimental observations of copper and stainless steel containing hydrogen.
Meaningful matches in stereovision.
Sabater, Neus; Almansa, Andrés; Morel, Jean-Michel
2012-05-01
This paper introduces a statistical method to decide whether two blocks in a pair of images match reliably. The method ensures that the selected block matches are unlikely to have occurred "just by chance." The new approach is based on the definition of a simple but faithful statistical background model for image blocks learned from the image itself. A theorem guarantees that under this model, not more than a fixed number of wrong matches occurs (on average) for the whole image. This fixed number (the number of false alarms) is the only method parameter. Furthermore, the number of false alarms associated with each match measures its reliability. This a contrario block-matching method, however, cannot rule out false matches due to the presence of periodic objects in the images. But it is successfully complemented by a parameterless self-similarity threshold. Experimental evidence shows that the proposed method also detects occlusions and incoherent motions due to vehicles and pedestrians in nonsimultaneous stereo. PMID:22442122
Odd perfect numbers have at least nine distinct prime factors
NASA Astrophysics Data System (ADS)
Nielsen, Pace P.
2007-12-01
An odd perfect number, N , is shown to have at least nine distinct prime factors. If 3nmid N then N must have at least twelve distinct prime divisors. The proof ultimately avoids previous computational results for odd perfect numbers.
An almost 'perfectly' diffuse, 'perfect' reflector for far-infrared reflectance calibration
NASA Technical Reports Server (NTRS)
Smith, Sheldon M.
1993-01-01
Specular and diffuse reflectance measurements made near normal incidence of two very rough, solid aluminum surfaces are presented for the wavelength range from 2.2 to 512 microns. The diffuse measurements made at nonspecular angles by two different detectors indicate that between 33 and 201 microns the reflectance of one surface is nearly Lambertian (isotropic) with a bidirectional reflectance distribution function (BRDF) value within 32 percent of the theoretical value of (1/pi)/sr for a perfectly diffuse, perfect reflector. Photometric reflectance spectra at the specular angle show that between 6.9 and 100 microns the specular BRDF of these surfaces is within 5 percent of the theoretical value of (1/pi)/sr. At longer wavelengths of 235, 320, and 512 microns the specular reflectance rapidly departs from that of a perfectly diffuse, perfect reflector. The two samples studied have rms surface roughnesses of 44 and 60 microns. A durable metal surface with these near perfect reflectance characteristics can be advantageously used in the FIR as a black-body source, the interior surface of an integrating sphere, and most especially as an absolute calibration standard. BRDF measurements at 40 deg incidence, though still highly diffuse, show a significant departure from Lambertian reflectance.
Computing the Casimir energy using the point-matching method
Lombardo, F. C.; Mazzitelli, F. D.; Vazquez, M.; Villar, P. I.
2009-09-15
We use a point-matching approach to numerically compute the Casimir interaction energy for a two perfect-conductor waveguide of arbitrary section. We present the method and describe the procedure used to obtain the numerical results. At first, our technique is tested for geometries with known solutions, such as concentric and eccentric cylinders. Then, we apply the point-matching technique to compute the Casimir interaction energy for new geometries such as concentric corrugated cylinders and cylinders inside conductors with focal lines.
A New Approach for Semantic Web Matching
NASA Astrophysics Data System (ADS)
Zamanifar, Kamran; Heidary, Golsa; Nematbakhsh, Naser; Mardukhi, Farhad
In this work we propose a new approach for semantic web matching to improve the performance of Web Service replacement. Because in automatic systems we should ensure the self-healing, self-configuration, self-optimization and self-management, all services should be always available and if one of them crashes, it should be replaced with the most similar one. Candidate services are advertised in Universal Description, Discovery and Integration (UDDI) all in Web Ontology Language (OWL). By the help of bipartite graph, we did the matching between the crashed service and a Candidate one. Then we chose the best service, which had the maximum rate of matching. In fact we compare two services' functionalities and capabilities to see how much they match. We found that the best way for matching two web services, is comparing the functionalities of them.
On the perfect hexagonal packing of rods
NASA Astrophysics Data System (ADS)
Starostin, E. L.
2006-04-01
In most cases the hexagonal packing of fibrous structures or rods extremizes the energy of interaction between strands. If the strands are not straight, then it is still possible to form a perfect hexatic bundle. Conditions under which the perfect hexagonal packing of curved tubular structures may exist are formulated. Particular attention is given to closed or cycled arrangements of the rods like in the DNA toroids and spools. The closure or return constraints of the bundle result in an allowable group of automorphisms of the cross-sectional hexagonal lattice. The structure of this group is explored. Examples of open helical-like and closed toroidal-like bundles are presented. An expression for the elastic energy of a perfectly packed bundle of thin elastic rods is derived. The energy accounts for both the bending and torsional stiffnesses of the rods. It is shown that equilibria of the bundle correspond to solutions of a variational problem formulated for the curve representing the axis of the bundle. The functional involves a function of the squared curvature under the constraints on the total torsion and the length. The Euler-Lagrange equations are obtained in terms of curvature and torsion and due to the existence of the first integrals the problem is reduced to the quadrature. The three-dimensional shape of the bundle may be readily reconstructed by integration of the Ilyukhin-type equations in special cylindrical coordinates. The results are of universal nature and are applicable to various fibrous structures, in particular, to intramolecular liquid crystals formed by DNA condensed in toroids or packed inside the viral capsids. International Workshop on Biopolymers: Thermodynamics, Kinetics and Mechanics of DNA, RNA and Proteins, 30.05.2005-3.06.2005, The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy.
Explaining evolution via constrained persistent perfect phylogeny
2014-01-01
Background The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. Results We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. Conclusions A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to
Coherent perfect absorption in chiral metamaterials.
Ye, Yuqian; Hay, Darrick; Shi, Zhimin
2016-07-15
We study the coherent perfect absorption (CPA) of a chiral structure and derive analytically the CPA condition for transversely isotropic chiral structures in circular polarization bases. The coherent absorption of such a chiral system is generally polarization dependent and can be tuned by the relative phase between the coherent input beams. To demonstrate our theoretical predictions, a chiral metamaterial absorber operating in the terahertz frequency range is optimized. We numerically demonstrate that a coherent absorption of 99.5% can be achieved. Moreover, we show that an optimized CPA chiral structure can be used as an interferometric control of polarization state of the output beams with constant output intensity. PMID:27420535
Efficient nonlinear generation of high power, higher order, ultrafast "perfect" vortices in green.
Apurv Chaitanya, N; Jabir, M V; Samanta, G K
2016-04-01
We report on efficient nonlinear generation of ultrafast, higher order "perfect" vortices at the green wavelength. Based on Fourier transformation of the higher order Bessel-Gauss (BG) beam generated through the combination of the spiral phase plate and axicon, we have transformed the Gaussian beam of the ultrafast Yb-fiber laser at 1060 nm into perfect vortices of power 4.4 W and order up to 6. Using single-pass second-harmonic generation (SHG) of such vortices in 5 mm long chirped MgO-doped, periodically poled congruent LiNbO_{3} crystal, we have generated perfect vortices at green wavelength (530 nm) with output power of 1.2 W and vortex order up to 12 at a single-pass conversion efficiency of 27%, independent of the orders. This is the highest single-pass SHG efficiency of any optical beams other than Gaussian beams. Unlike the disintegration of higher order vortices due to spatial walk-off effect in birefringent crystals, here, the use of the quasi-phase-matching process enables generation of high-quality vortices, even at higher orders. The green perfect vortices of all orders have temporal and spectral widths of 507 fs and 1.9 nm, respectively, corresponding to a time-bandwidth product of 1.02. PMID:27192233
Wideband polarization-insensitive metamaterial absorber with perfect dual resonances
NASA Astrophysics Data System (ADS)
Ayop, Osman; Rahim, Mohamad Kamal A.; Murad, Noor Asniza; Samsuri, Noor Asmawati
2016-04-01
This paper presents the analysis of wideband polarization-insensitive metamaterial absorber with perfect dual resonances. The structure is designed using lossy FR4 substrate with copper layers. The resonating elements are designed using the combination of circular ring with modified circle-shaped structure. The resonating elements are printed on the top surface of FR4 substrate, while the bottom surface is printed with full copper ground plane. From the simulation, the proposed design achieves nearly perfect absorbance at dual resonant frequency with improved bandwidth compared to the general circular ring design. Two peaks absorbance of 98.66 and 99.84 % are observed at 9.81 and 10.41 GHz respectively with full width half maximum (FWHM) bandwidth of 1050 MHz or 10.38 % at normal incident EM wave. The structure is also simulated for different polarization angles and it is observed that the structure can maintain the absorbance characteristic for all polarization angles. The experimental work is done to validate the simulated result. It is confirmed that two peaks absorbance are achieved with magnitudes of 99.88 and 99.67 % at 10.14 and 10.79 GHz, respectively. The measured FWHM is 1160 MHz.
NASA Astrophysics Data System (ADS)
Kupers, Michiel; Klingbeil, Patrick; Tschischgale, Joerg; Buhl, Stefan; Hempel, Fritjof
2009-03-01
Cost of ownership of scanners for the manufacturing of front end layers is becoming increasingly expensive. The ability to quickly switch the production of a layer to another scanner in case it is down is important. This paper presents a method to match the scanner grids in the most optimal manner so that use of front end scanners in effect becomes interchangeable. A breakdown of the various components of overlay is given and we discuss methods to optimize the matching strategy in the fab. A concern here is how to separate the scanner and process induced effects. We look at the relative contributions of intrafield and interfield errors caused by the scanner and the process. Experimental results of a method to control the scanner grid are presented and discussed. We compare the overlay results before and after optimizing the scanner grids and show that the matching penalty is reduced by 20%. We conclude with some thoughts on the need to correct the remaining matching errors.
NASA Technical Reports Server (NTRS)
Wolfe, R. H., Jr.; Juday, R. D.
1982-01-01
Interimage matching is the process of determining the geometric transformation required to conform spatially one image to another. In principle, the parameters of that transformation are varied until some measure of some difference between the two images is minimized or some measure of sameness (e.g., cross-correlation) is maximized. The number of such parameters to vary is faily large (six for merely an affine transformation), and it is customary to attempt an a priori transformation reducing the complexity of the residual transformation or subdivide the image into small enough match zones (control points or patches) that a simple transformation (e.g., pure translation) is applicable, yet large enough to facilitate matching. In the latter case, a complex mapping function is fit to the results (e.g., translation offsets) in all the patches. The methods reviewed have all chosen one or both of the above options, ranging from a priori along-line correction for line-dependent effects (the high-frequency correction) to a full sensor-to-geobase transformation with subsequent subdivision into a grid of match points.
Rigby, Perry G; Gururaja, Ramnarayan Paragi; Hilton, Charles
2015-01-01
The Medical Education Commission (MEC) has published Graduate Medical Education (GME) data since 1997, including the National Residency Matching Program (NRMP) and the Supplemental Offer and Acceptance Program (SOAP), and totals all GME in Louisiana for annual publication. The NRMP provides the quotas and filled positions by institution. Following the NRMP, SOAP attempts to place unmatched candidates with slots that are unfilled. The NRMP Fellowship match also comes close to filling quotas and has a significant SOAP. Thus, an accurate number of total filled positions is best obtained in July of the same match year. All GME programs in Louisiana are represented for 2014, and the number trend 2005 to 2014 shows that the only dip was post-Katrina in 2005-2006. The March match after SOAP 2014 is at the peak for both senior medical students and post graduate year one (PGY-1) residents. A significant and similar number stay in Louisiana GME institutions after graduation. Also noteworthy is that a lower percentage are staying in state, due to increased enrollment in all Louisiana medical schools. PMID:27159458
Filterbank-based fingerprint matching.
Jain, A K; Prabhakar, S; Hong, L; Pankanti, S
2000-01-01
With identity fraud in our society reaching unprecedented proportions and with an increasing emphasis on the emerging automatic personal identification applications, biometrics-based verification, especially fingerprint-based identification, is receiving a lot of attention. There are two major shortcomings of the traditional approaches to fingerprint representation. For a considerable fraction of population, the representations based on explicit detection of complete ridge structures in the fingerprint are difficult to extract automatically. The widely used minutiae-based representation does not utilize a significant component of the rich discriminatory information available in the fingerprints. Local ridge structures cannot be completely characterized by minutiae. Further, minutiae-based matching has difficulty in quickly matching two fingerprint images containing a different number of unregistered minutiae points. The proposed filter-based algorithm uses a bank of Gabor filters to capture both local and global details in a fingerprint as a compact fixed length FingerCode. The fingerprint matching is based on the Euclidean distance between the two corresponding FingerCodes and hence is extremely fast. We are able to achieve a verification accuracy which is only marginally inferior to the best results of minutiae-based algorithms published in the open literature. Our system performs better than a state-of-the-art minutiae-based system when the performance requirement of the application system does not demand a very low false acceptance rate. Finally, we show that the matching performance can be improved by combining the decisions of the matchers based on complementary (minutiae-based and filter-based) fingerprint information. PMID:18255456
NASA Astrophysics Data System (ADS)
Li, Liang; Yang, Lin-An; Xue, Jun-Shuai; Cao, Rong-Tao; Xu, Sheng-Rui; Zhang, Jin-Cheng; Hao, Yue
2014-06-01
We report on an improvement in the crystal quality of GaN film with an In0.17Al0.83N interlayer grown by pulsed metal—organic chemical vapor deposition, which is in-plane lattice-matched to GaN films. The indium composition of about 17% and the reductions of both screw and edge threading dislocations (TDs) in GaN film with the InAlN interlayer are estimated by high resolution X-ray diffraction. Transmission electron microscopy (TEM) measurements are employed to understand the mechanism of reduction in TD density. Raman and photoluminescence measurements indicate that the InAlN interlayer can improve the crystal quality of GaN film, and verify that there is no additional residual stress induced into the GaN film with InAlN interlayer. Atomic force microscopy measurement shows that the InAlN interlayer brings in a smooth surface morphology of GaN film. All the results show that the insertion of the InAlN interlayer is a convenient method to achieve excellent crystal quality in GaN epitaxy.
Perfect magnetohydrodynamics as a field theory
Bekenstein, Jacob D.; Betschart, Gerold
2006-10-15
We propose the generally covariant action for the theory of a self-coupled complex scalar field and electromagnetism which by virtue of constraints is equivalent, in the regime of long wavelengths, to perfect magnetohydrodynamics (MHD). We recover from it the Euler equation with Lorentz force, and the thermodynamic relations for a prefect fluid. The equation of state of the latter is related to the scalar field's self potential. We introduce 1+3 notation to elucidate the relation between MHD and field variables. In our approach the requirement that the scalar field be single valued leads to the quantization of a certain circulation in steps of ({Dirac_h}/2{pi}); this feature leads, in the classical limit, to the conservation of that circulation. The circulation is identical to that in Oron's generalization of Kelvin's circulation theorem to perfect MHD; we here characterize the new conserved helicity associated with it. We also demonstrate the existence for MHD of two Bernoulli-like theorems for each spacetime symmetry of the flow and geometry; one of these is pertinent to suitably defined potential flow. We exhibit the conserved quantities explicitly in the case that two symmetries are simultaneously present, and give examples. Also in this case we exhibit a new conserved MHD circulation distinct from Oron's, and provide an example.
Metamaterial perfect absorber based hot electron photodetection.
Li, Wei; Valentine, Jason
2014-06-11
While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991
Sublithographic Architecture: Shifting the Responsibility for Perfection
NASA Astrophysics Data System (ADS)
Dehon, A.
In the past, processing had orders of magnitude between devices and atoms (e.g., with silicon atom lattice spacing around 0.5 nm, a minimum size feature was roughly 2000 atoms wide when we had 1 μm feature sizes). It was the process engineer's job to craft this large collection of atoms into "perfect" devices. The circuit designer and architect could then design systems knowing the process engineer would always give them a set of perfect devices. As we continue to shrink our devices, we no longer have orders of magnitude between the devices and the atoms. As a result, the circuit designers and architects are beginning to work within a similar realm of atoms. Consequently, they must assume some of the responsibilities for dealing with atomic-scale imperfections and uncertainty. This demands a significant shift in our abstraction hierarchy, the responsibilities and expectations at each level in this hierarchy, our fabrication techniques, our testing strategies, and our approaches to design for these atomic-scale computing systems.
Broadband Reflectionless Metasheets: Frequency-Selective Transmission and Perfect Absorption
NASA Astrophysics Data System (ADS)
Asadchy, V. S.; Faniayeu, I. A.; Ra'di, Y.; Khakhomov, S. A.; Semchenko, I. V.; Tretyakov, S. A.
2015-07-01
Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin resonant absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper, we explore possibilities to realize a thin absorbing layer that produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a thin resonant absorber, invisible in reflection in a very wide frequency range, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cell, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit cell but compensating the field coupling at the macroscopic level. We prove that the concept and the proposed realization approach also can be used to create nonreflecting layers for full control of transmitted fields. Our results can have a broad range of potential applications over the entire electromagnetic spectrum including, for example, perfect ultracompact wave filters and selective multifrequency sensors.
ERIC Educational Resources Information Center
Ozier, Lance
2011-01-01
Pressure for students to produce writing perfection in the classroom often eclipses the emphasis placed on the need for students to practice writing. Occasions for students to choose, challenge, and reflect--to actually risk risking--are too often absent from conversations among students and teachers in countless English classrooms. Tom Romano…
Matching current windstorms to historical analogues
NASA Astrophysics Data System (ADS)
Becker, Bernd; Maisey, Paul; Scannell, Claire; Vanvyve, Emilie; Mitchell, Lorna; Steptoe, Hamish
2015-04-01
assessment of the goodness of fit made by the rank proximity measure. Using this technique a series of potential historical footprints matching the current footprint is found. Each potential match is indexed according to its closeness to the current footprint where an index rating of 0 is a perfect match or "identical twin". Such pattern matching of current and forecast windstorms against an historical archive can enable insurers estimate a rapid prediction of likely loss and aid the timely deployment of staff and funds at the right level.
Dohn, Anders; Garza-Villarreal, Eduardo A.; Heaton, Pamela; Vuust, Peter
2012-01-01
Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increased prevalence of AP in individuals with sensory and developmental disorders. Here, we determine whether individual autistic traits are present in people with AP. We quantified subclinical levels of autism traits using the Autism-Spectrum Quotient (AQ) in three matched groups of subjects: 16 musicians with AP (APs), 18 musicians without AP (non-APs), and 16 non-musicians. In addition, we measured AP ability by a pitch identification test with sine wave tones and piano tones. We found a significantly higher degree of autism traits in APs than in non-APs and non-musicians, and autism scores were significantly correlated with pitch identification scores (r = .46, p = .003). However, our results showed that APs did not differ from non-APs on diagnostically crucial social and communicative domain scores and their total AQ scores were well below clinical thresholds for autism. Group differences emerged on the imagination and attention switching subscales of the AQ. Thus, whilst these findings do link AP with autism, they also show that AP ability is most strongly associated with personality traits that vary widely within the normal population. PMID:22666425
Dohn, Anders; Garza-Villarreal, Eduardo A; Heaton, Pamela; Vuust, Peter
2012-01-01
Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increased prevalence of AP in individuals with sensory and developmental disorders. Here, we determine whether individual autistic traits are present in people with AP. We quantified subclinical levels of autism traits using the Autism-Spectrum Quotient (AQ) in three matched groups of subjects: 16 musicians with AP (APs), 18 musicians without AP (non-APs), and 16 non-musicians. In addition, we measured AP ability by a pitch identification test with sine wave tones and piano tones. We found a significantly higher degree of autism traits in APs than in non-APs and non-musicians, and autism scores were significantly correlated with pitch identification scores (r = .46, p = .003). However, our results showed that APs did not differ from non-APs on diagnostically crucial social and communicative domain scores and their total AQ scores were well below clinical thresholds for autism. Group differences emerged on the imagination and attention switching subscales of the AQ. Thus, whilst these findings do link AP with autism, they also show that AP ability is most strongly associated with personality traits that vary widely within the normal population. PMID:22666425
Threefold entanglement matching
NASA Astrophysics Data System (ADS)
Roa, Luis; Muñoz, Ariana; Hutin, Alice; Hecker, Matthias
2015-11-01
We address the problem of entanglement matching in the probabilistic teleportation scheme by considering two independent levels of entanglement in the measurement basis. The probability of a successful teleportation has an upper bound which only depends on the amount of entanglement of the quantum channel. However, we found that each entanglement of the measurement basis contributes independently to the success probability as long as it is weaker than the entanglement of the channel. Accordingly, the teleportation process reaches its optimal probability when both entanglements of the measurement basis match the entanglement of the channel. Additionally, we study the probabilistic scheme for extracting an unknown state from a partially known state. We characterize the success probability and the concurrence involved in that process.
Gas cooler sets the perfect balance
Bilder, M.; Aubry, L.; Schwartz, G.; Anderson, R.; Burkhardt, C. ); Wilson, J.; Vallort, J.; Ransick, M.F. )
1993-05-20
In July 1991, a 65-ton electric chiller was in need of major repair at NutraSweet's R and D facility outside of Chicago. Instead of automatically repairing or replacing that chiller, NutraSweet engineers Larry Aubry and Gerald Schwartz began to look at other alternatives. What they discovered was that a natural gas absorption chiller was a cost-effective, environmentally safe alternative effective, environmentally safe alternative perfectly suited for their application. The benefits for NutraSweet are straightforward: energy bills have been cut by more than [dollar sign]70,000 annually, existing boiler capacity is better utilized, existing electrical cooling system life is extended, maintenance costs are reduced, and no-ozone-depleting CFCs are utilized by the natural gas chiller. Simple payback on the unit, originally expected to be almost four years, has been reduced to closer to three.
An approach towards a perfect thermal diffuser
NASA Astrophysics Data System (ADS)
Vemuri, Krishna P.; Bandaru, Prabhakar R.
2016-07-01
A method for the most efficient removal of heat, through an anisotropic composite, is proposed. It is shown that a rational placement of constituent materials, in the radial and the azimuthal directions, at a given point in the composite yields a uniform temperature distribution in spherical diffusers. Such arrangement is accompanied by a very significant reduction of the source temperature, in principle, to infinitesimally above the ambient temperature and forms the basis for the design of a perfect thermal diffuser with maximal heat dissipation. Orders of magnitude enhanced performance, compared to that obtained through the use of a diffuser constituted from a single material with isotropic thermal conductivity has been observed and the analytical principles underlying the design were validated through extensive computational simulations.
An approach towards a perfect thermal diffuser
Vemuri, Krishna P.; Bandaru, Prabhakar R.
2016-01-01
A method for the most efficient removal of heat, through an anisotropic composite, is proposed. It is shown that a rational placement of constituent materials, in the radial and the azimuthal directions, at a given point in the composite yields a uniform temperature distribution in spherical diffusers. Such arrangement is accompanied by a very significant reduction of the source temperature, in principle, to infinitesimally above the ambient temperature and forms the basis for the design of a perfect thermal diffuser with maximal heat dissipation. Orders of magnitude enhanced performance, compared to that obtained through the use of a diffuser constituted from a single material with isotropic thermal conductivity has been observed and the analytical principles underlying the design were validated through extensive computational simulations. PMID:27404569
A perfect launch viewed across Banana Creek
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Discovery seems to burst forth from a pillow of smoke as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The brilliant light from the solid rocket booster flames is reflected in nearby water. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.
A perfect launch viewed across Banana Creek
NASA Technical Reports Server (NTRS)
2000-01-01
Billows of smoke and steam surround Space Shuttle Discovery as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.
An approach towards a perfect thermal diffuser.
Vemuri, Krishna P; Bandaru, Prabhakar R
2016-01-01
A method for the most efficient removal of heat, through an anisotropic composite, is proposed. It is shown that a rational placement of constituent materials, in the radial and the azimuthal directions, at a given point in the composite yields a uniform temperature distribution in spherical diffusers. Such arrangement is accompanied by a very significant reduction of the source temperature, in principle, to infinitesimally above the ambient temperature and forms the basis for the design of a perfect thermal diffuser with maximal heat dissipation. Orders of magnitude enhanced performance, compared to that obtained through the use of a diffuser constituted from a single material with isotropic thermal conductivity has been observed and the analytical principles underlying the design were validated through extensive computational simulations. PMID:27404569
Electromagnetic Detection of a Perfect Carpet Cloak
NASA Astrophysics Data System (ADS)
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-05-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics.
Electromagnetic Detection of a Perfect Carpet Cloak
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-01-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798
The failure strengths of perfect diamond crystals
NASA Technical Reports Server (NTRS)
Whitlock, J.; Ruoff, A. L.
1981-01-01
Finite elasticity analysis is extended to the 110 direction, where off axis strain symmetry is not present, and the third order elastic data are obtained for diamond. The compressive yield strengths of perfect diamond crystals loaded in the 100, 110, and 111 directions are predicted to be 2.2, 5.6, and 2.8 Mbars, respectively, while the corresponding tensile fracture strengths are 1.0, 0.5, and 0.5 Mbars. From these results and from Hertz theory it is predicted that ring fracture of spherically tipped diamonds pressed against a flat will occur at pressures of 1.8-1.9 Mbars, substantially below the yield pressure (above 3 Mbars). Modification of the tip shape leads to a predicted increase in the pressure at which fracture occurs.
A perfect launch of Space Shuttle Discovery
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Discovery lifts off Launch Pad 39A against a backdrop of xenon lights (just above the orbiter' nose and at left). On the Mobile Launcher Platform beneath, water begins flooding the area for flame and sound control. The perfect on- time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.
Electromagnetic detection of a perfect carpet cloak.
Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile
2015-01-01
It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798
LensPerfect Analysis of Abell 1689
NASA Astrophysics Data System (ADS)
Coe, Dan A.
2007-12-01
I present the first massmap to perfectly reproduce the position of every gravitationally-lensed multiply-imaged galaxy detected to date in ACS images of Abell 1689. This massmap was obtained using a powerful new technique made possible by a recent advance in the field of Mathematics. It is the highest resolution assumption-free Dark Matter massmap to date, with the resolution being limited only by the number of multiple images detected. We detect 8 new multiple image systems and identify multiple knots in individual galaxies to constrain a grand total of 168 knots within 135 multiple images of 42 galaxies. No assumptions are made about mass tracing light, and yet the brightest visible structures in A1689 are reproduced in our massmap, a few with intriguing positional offsets. Our massmap probes radii smaller than that resolvable in current Dark Matter simulations of galaxy clusters. And at these radii, we observe slight deviations from the NFW and Sersic profiles which describe simulated Dark Matter halos so well. While we have demonstrated that our method is able to recover a known input massmap (to limited resolution), further tests are necessary to determine the uncertainties of our mass profile and positions of massive subclumps. I compile the latest weak lensing data from ACS, Subaru, and CFHT, and attempt to fit a single profile, either NFW or Sersic, to both the observed weak and strong lensing. I confirm the finding of most previous authors, that no single profile fits extremely well to both simultaneously. Slight deviations are revealed, with the best fits slightly over-predicting the mass profile at both large and small radius. Our easy-to-use software, called LensPerfect, will be made available soon. This research was supported by the European Commission Marie Curie International Reintegration Grant 017288-BPZ and the PNAYA grant AYA2005-09413-C02.
Results from the VALUE perfect predictor experiment: process-based evaluation
NASA Astrophysics Data System (ADS)
Maraun, Douglas; Soares, Pedro; Hertig, Elke; Brands, Swen; Huth, Radan; Cardoso, Rita; Kotlarski, Sven; Casado, Maria; Pongracz, Rita; Bartholy, Judit
2016-04-01
Until recently, the evaluation of downscaled climate model simulations has typically been limited to surface climatologies, including long term means, spatial variability and extremes. But these aspects are often, at least partly, tuned in regional climate models to match observed climate. The tuning issue is of course particularly relevant for bias corrected regional climate models. In general, a good performance of a model for these aspects in present climate does therefore not imply a good performance in simulating climate change. It is now widely accepted that, to increase our condidence in climate change simulations, it is necessary to evaluate how climate models simulate relevant underlying processes. In other words, it is important to assess whether downscaling does the right for the right reason. Therefore, VALUE has carried out a broad process-based evaluation study based on its perfect predictor experiment simulations: the downscaling methods are driven by ERA-Interim data over the period 1979-2008, reference observations are given by a network of 85 meteorological stations covering all European climates. More than 30 methods participated in the evaluation. In order to compare statistical and dynamical methods, only variables provided by both types of approaches could be considered. This limited the analysis to conditioning local surface variables on variables from driving processes that are simulated by ERA-Interim. We considered the following types of processes: at the continental scale, we evaluated the performance of downscaling methods for positive and negative North Atlantic Oscillation, Atlantic ridge and blocking situations. At synoptic scales, we considered Lamb weather types for selected European regions such as Scandinavia, the United Kingdom, the Iberian Pensinsula or the Alps. At regional scales we considered phenomena such as the Mistral, the Bora or the Iberian coastal jet. Such process-based evaluation helps to attribute biases in surface
Feedback as the source of imperfection in lossy perfect lenses
NASA Astrophysics Data System (ADS)
Rosenblatt, Gilad; Bartal, Guy; Orenstein, Meir
2016-02-01
The major barrier to realizing a perfect lens with left-handed materials is perceived to be their intrinsic loss. Here we show that only specific designs of perfect lenses are limited by loss—those in which material loss is translated to internal feedback. The asymptotically uniform transmission required for perfect lensing is hindered by such feedback, which generates resonances that lead to a spatial cutoff in the lens transmission. Moreover, uniform transmission and its resonant deterioration stem from completely separate classes of modal excitations. A perfect lens made of lossy left-handed materials is therefore not forbidden in principle. Pursuing perfect lens designs that avoid internal feedback offers a path towards realization of practical perfect lenses.
Will a perfect model agree with perfect observations? The impact of spatial sampling
NASA Astrophysics Data System (ADS)
Schutgens, Nick A. J.; Gryspeerdt, Edward; Weigum, Natalie; Tsyro, Svetlana; Goto, Daisuke; Schulz, Michael; Stier, Philip
2016-05-01
The spatial resolution of global climate models with interactive aerosol and the observations used to evaluate them is very different. Current models use grid spacings of ˜ 200 km, while satellite observations of aerosol use so-called pixels of ˜ 10 km. Ground site or airborne observations relate to even smaller spatial scales. We study the errors incurred due to different resolutions by aggregating high-resolution simulations (10 km grid spacing) over either the large areas of global model grid boxes ("perfect" model data) or small areas corresponding to the pixels of satellite measurements or the field of view of ground sites ("perfect" observations). Our analysis suggests that instantaneous root-mean-square (RMS) differences of perfect observations from perfect global models can easily amount to 30-160 %, for a range of observables like AOT (aerosol optical thickness), extinction, black carbon mass concentrations, PM2.5, number densities and CCN (cloud condensation nuclei). These differences, due entirely to different spatial sampling of models and observations, are often larger than measurement errors in real observations. Temporal averaging over a month of data reduces these differences more strongly for some observables (e.g. a threefold reduction for AOT), than for others (e.g. a twofold reduction for surface black carbon concentrations), but significant RMS differences remain (10-75 %). Note that this study ignores the issue of temporal sampling of real observations, which is likely to affect our present monthly error estimates. We examine several other strategies (e.g. spatial aggregation of observations, interpolation of model data) for reducing these differences and show their effectiveness. Finally, we examine consequences for the use of flight campaign data in global model evaluation and show that significant biases may be introduced depending on the flight strategy used.
Multinomial pattern matching revisited
NASA Astrophysics Data System (ADS)
Horvath, Matthew S.; Rigling, Brian D.
2015-05-01
Multinomial pattern matching (MPM) is an automatic target recognition algorithm developed for specifically radar data at Sandia National Laboratories. The algorithm is in a family of algorithms that first quantizes pixel value into Nq bins based on pixel amplitude before training and classification. This quantization step reduces the sensitivity of algorithm performance to absolute intensity variation in the data, typical of radar data where signatures exhibit high variation for even small changes in aspect angle. Our previous work has focused on performance analysis of peaky template matching, a special case of MPM where binary quantization is used (Nq = 2). Unfortunately references on these algorithms are generally difficult to locate and here we revisit the MPM algorithm and illustrate the underlying statistical model and decision rules for two algorithm interpretations: the 1-of-K vector form and the scalar. MPM can also be used as a detector and specific attention is given to algorithm tuning where "peak pixels" are chosen based on their underlying empirical probabilities according to a reward minimization strategy aimed at reducing false alarms in the detection scenario and false positives in a classification capacity. The algorithms are demonstrated using Monte Carlo simulations on the AFRL civilian vehicle dataset for variety of choices of Nq.
NASA Astrophysics Data System (ADS)
Bergeaud, Francois; Mallat, Stephane G.
1995-04-01
A crucial problem in image analysis is to construct efficient low-level representations of an image, providing precise characterization of features which compose it, such as edges and texture components. An image usually contains very different types of features, which have been successfully modeled by the very redundant family of 2D Gabor oriented wavelets, describing the local properties of the image: localization, scale, preferred orientation, amplitude and phase of the discontinuity. However, this model generates representations of very large size. Instead of decomposing a given image over this whole set of Gabor functions, we use an adaptive algorithm (called matching pursuit) to select the Gabor elements which approximate at best the image, corresponding to the main features of the image. This produces compact representation in terms of few features that reveal the local image properties. Results prove that the elements are precisely localized on the edges of the images, and give a local decomposition as linear combinations of `textons' in the textured regions. We introduce a fast algorithm to compute the matching pursuit decomposition for images with a complexity of (Omicron) (N log2 N) per iteration for an image of N2 pixels.
Challenging the standard perfect fluid paradigm
NASA Astrophysics Data System (ADS)
O'Brien, James
2015-04-01
We show that the standard perfect fluid paradigm is not necessarily a valid description of a curved space steady state gravitational source. Simply by virtue of not being flat, curved space geometries have to possess intrinsic length scales, and such length scales can affect the fluid structure.We show that for the specific case of a static, spherically symmetric geometry, the steady state energy-momentum tensor that ensues will in general be of the form Tμν =(ρ + p) UμUν + pgμν + qπμν where πμν is a symmetric, traceless rank two tensor which obeys Uμπμν = 0 . Such a qπμν type term is absent for an incoherently averaged steady state fluid in a spacetime where there are no intrinsic length scales, and in principle would thus be missed in a covariantizing of a flat spacetime Tμν. While it is reassuring that we find that in practice the effect of such qπμν type terms is small for weak gravity stars, for strong gravity systems their potential influence would need to be explored.
Perfect terahertz absorber using fishnet based metafilm
Azad, Abul Kalam; Shchegolkov, Dmitry Yu; Chen, Houtong; Taylor, Antoinette; Smirnova, E I; O' Hara, John F
2009-01-01
We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.
Do audition electives impact match success?
Higgins, Elizabeth; Newman, Linnie; Halligan, Katherine; Miller, Margaret; Schwab, Sally; Kosowicz, Lynn
2016-01-01
Purpose The authors sought to determine the value of the audition elective to the overall success of medical students in the match. Method The authors surveyed 1,335 fourth-year medical students at 10 medical schools in 2013. The study took place over a 2-month period immediately following the match. Medical students were emailed a 14-question survey and asked about audition electives, rank order, and cost of ‘away’ rotations. Results One hundred percent of students wishing to match in otolaryngology, neurosurgery, plastic surgery, radiation oncology, and urology took the audition electives. The difference by specialty in the proportion of students who took an audition was statistically significant (p<0.001). Of the students who auditioned, 71% matched at one of their top three choices compared with 84% of non-auditioners who matched to one of their top three choices (p<0.01). Conclusions Students performed a large number of ‘away’ rotations as ‘auditions’ in order to improve their chances in the match. For certain competitive specialties, virtually all students auditioned. Overall, students who did not audition were just as successful as or more successful than students who did audition. PMID:27301380
Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, Nigel A.; Grosman, Leore
2012-01-01
Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha‘ar HaGolan and Munhata (first half of the 8th millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as “clay pestles,” “clay rods,” and “cylindrical clay objects.” Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches. PMID:22870306
Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, A Nigel; Goring-Morris, Nigel A; Grosman, Leore
2012-01-01
Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha'ar HaGolan and Munhata (first half of the 8(th) millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as "clay pestles," "clay rods," and "cylindrical clay objects." Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches. PMID:22870306
Distinctiveness Maps for Image Matching
NASA Technical Reports Server (NTRS)
Manduchi, Roberto; Tomasi, Carlo
2000-01-01
Stereo correspondence is hard because different image features can look alike. We propose a measure for the ambiguity of image points that allows matching distinctive points first and breaks down the matching task into smaller and separate subproblems. Experiments with an algorithm based on this measure demonstrate the ensuing efficiency and low likelihood of incorrect matches.
Perfect Parenting: The Dictionary of 1,000 Parenting Tips.
ERIC Educational Resources Information Center
Pantley, Elizabeth
Using a dictionary format, this book addresses many of the issues faced by parents. Following an introduction that defines "perfect parenting" and lists nine "perfect parenting keys," topics are arranged alphabetically. Under each topic, a situation is stated, thoughts about the situation are offered, and solutions are suggested. Topics include…
The Perfective Past Tense in Greek Child Language
ERIC Educational Resources Information Center
Stavrakaki, Stavroula; Clahsen, Harald
2009-01-01
This study examines the perfective past tense of Greek in an elicited production and an acceptability judgment task testing 35 adult native speakers and 154 children in six age groups (age range: 3;5 to 8;5) on both existing and novel verb stimuli. We found a striking contrast between sigmatic and non-sigmatic perfective past tense forms. Sigmatic…
A multiband perfect absorber based on hyperbolic metamaterials
Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R.; Gurkan, Umut A.; Strangi, Giuseppe
2016-01-01
In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors. PMID:27188789
A multiband perfect absorber based on hyperbolic metamaterials.
Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R; Gurkan, Umut A; Strangi, Giuseppe
2016-01-01
In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors. PMID:27188789
A multiband perfect absorber based on hyperbolic metamaterials
NASA Astrophysics Data System (ADS)
Sreekanth, Kandammathe Valiyaveedu; Elkabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R.; Gurkan, Umut A.; Strangi, Giuseppe
2016-05-01
In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors.
NASA Astrophysics Data System (ADS)
Zhen, L.; Gong, Y. X.; Jiang, J. T.; Xu, C. Y.; Shao, W. Z.; Liu, P.; Tang, J.
2011-04-01
CoFe/Al2O3 composite nanoparticles were successfully prepared by hydrogen-thermally reducing cobalt aluminum ferrite. Compared with CoFe alloy nanoparticles, the permeability of CoFe/Al2O3 composite nanoparticles was remarkably enhanced and an improved impedance characteristic was achieved due to the introduction of insulated Al2O3. A multilayer absorber with CoFe/Al2O3 composite nanoparticles as the impedance matching layer and CoFe nanoflake as the dissipation layer was designed by using genetic algorithm, in which an ultrawide operation frequency bandwidth over 2.5-18 GHz was obtained. The microwave absorption performance in both normal and oblique incident case was evaluated by using electromagnetic simulator. The backward radar cross-section (RCS) was decreased at least 10 dB over a wide frequency range by covering the multilayer absorber on the surface of perfect electrical conductive plate.
Constraint-based stereo matching
NASA Technical Reports Server (NTRS)
Kuan, D. T.
1987-01-01
The major difficulty in stereo vision is the correspondence problem that requires matching features in two stereo images. Researchers describe a constraint-based stereo matching technique using local geometric constraints among edge segments to limit the search space and to resolve matching ambiguity. Edge segments are used as image features for stereo matching. Epipolar constraint and individual edge properties are used to determine possible initial matches between edge segments in a stereo image pair. Local edge geometric attributes such as continuity, junction structure, and edge neighborhood relations are used as constraints to guide the stereo matching process. The result is a locally consistent set of edge segment correspondences between stereo images. These locally consistent matches are used to generate higher-level hypotheses on extended edge segments and junctions to form more global contexts to achieve global consistency.
NASA Astrophysics Data System (ADS)
Jiang, Nan; Dang, Yijie; Wang, Jian
2016-06-01
Quantum image processing (QIP) means the quantum-based methods to speed up image processing algorithms. Many quantum image processing schemes claim that their efficiency is theoretically higher than their corresponding classical schemes. However, most of them do not consider the problem of measurement. As we all know, measurement will lead to collapse. That is to say, executing the algorithm once, users can only measure the final state one time. Therefore, if users want to regain the results (the processed images), they must execute the algorithms many times and then measure the final state many times to get all the pixels' values. If the measurement process is taken into account, whether or not the algorithms are really efficient needs to be reconsidered. In this paper, we try to solve the problem of measurement and give a quantum image matching algorithm. Unlike most of the QIP algorithms, our scheme interests only one pixel (the target pixel) instead of the whole image. It modifies the probability of pixels based on Grover's algorithm to make the target pixel to be measured with higher probability, and the measurement step is executed only once. An example is given to explain the algorithm more vividly. Complexity analysis indicates that the quantum scheme's complexity is O(2n) in contradistinction to the classical scheme's complexity O(2^{2n+2m}) , where m and n are integers related to the size of images.
Kaizen and ergonomics: the perfect marriage.
Rodriguez, Martin Antonio; Lopez, Luis Fernando
2012-01-01
This paper is an approach of how Kaizen (Continuous Improvement) and Ergonomics could be implemented in the field of work. The Toyota's Team Members are the owners of this job, applying tools and techniques to improve work conditions using the Kaizen Philosophy in a QCC Activity (Quality Control Circle). PMID:22316846
Matching roots to their environment
White, Philip J.; George, Timothy S.; Gregory, Peter J.; Bengough, A. Glyn; Hallett, Paul D.; McKenzie, Blair M.
2013-01-01
Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future. PMID:23821619
Computer code for determination of thermally perfect gas properties
NASA Technical Reports Server (NTRS)
Witte, David W.; Tatum, Kenneth E.
1994-01-01
A set of one-dimensional compressible flow relations for a thermally perfect, calorically imperfect gas is derived for the specific heat c(sub p), expressed as a polynomial function of temperature, and developed into the thermally perfect gas (TPG) computer code. The code produces tables of compressible flow properties similar to those of NACA Rep. 1135. Unlike the tables of NACA Rep. 1135 which are valid only in the calorically perfect temperature regime, the TPG code results are also valid in the thermally perfect calorically imperfect temperature regime which considerably extends the range of temperature application. Accuracy of the TPG code in the calorically perfect temperature regime is verified by comparisons with the tables of NACA Rep. 1135. In the thermally perfect, calorically imperfect temperature regime, the TPG code is validated by comparisons with results obtained from the method of NACA Rep. 1135 for calculating the thermally perfect calorically imperfect compressible flow properties. The temperature limits for application of the TPG code are also examined. The advantage of the TPG code is its applicability to any type of gas (monatomic, diatomic, triatomic, or polyatomic) or any specified mixture thereof, whereas the method of NACA Rep. 1135 is restricted to only diatomic gases.
LU factorization of perfect-reconstruction filter bank
NASA Astrophysics Data System (ADS)
Kok, C. W.; Nguyen, Truong Q.
1997-04-01
This paper presents a new time-domain-based factorization algorithm for perfect-reconstruction filter bank. In the proposed algorithm, the polyphase transfer matrix is decomposed into elementary blocks using LU representation which can also be implemented by ladder structure. Consequently, perfect reconstruction is structurally imposed and the resulting system is robust to coefficient quantization. We presented an iterative design procedure to obtain perfect reconstruction filter bank with different desired specification on each subband filters. Given several subband filters, a block LU factorization algorithm is presented for perfect reconstruction filter bank completion. Special properties such as linear phase and FIR solution are discussed and parameterization of paraunitary completion under block LU factorization is derived. Block ladder structure are presented for efficient implementation. The proposed structure can be used to design perfect reconstruction filter bank with higher dimension. An example in mapping of 1D perfect reconstruction filter bank with LU representation into 2D perfect reconstruction filter bank with diamond shaped passband using nonrectangular transform is discussed.
Computer-Generated Holographic Matched Filters
NASA Astrophysics Data System (ADS)
Butler, Steven Frank
This dissertation presents techniques for the use of computer-generated holograms (CGH) for matched filtering. An overview of the supporting technology is provided. Included are techniques for modifying existing CGH algorithms to serve as matched filters in an optical correlator. It shows that matched filters produced in this fashion can be modified to improve the signal-to-noise and efficiency over that possible with conventional holography. The effect and performance of these modifications are demonstrated. In addition, a correction of film non-linearity in continuous -tone filter production is developed. Computer simulations provide quantitative and qualitative demonstration of theoretical principles, with specific examples validated in optical hardware. Conventional and synthetic holograms, both bleached and unbleached, are compared.
Lattice-Matched Semiconductor Layers on Single Crystalline Sapphire Substrate
NASA Technical Reports Server (NTRS)
Choi, Sang; King, Glen; Park, Yeonjoon
2009-01-01
SiGe is an important semiconductor alloy for high-speed field effect transistors (FETs), high-temperature thermoelectric devices, photovoltaic solar cells, and photon detectors. The growth of SiGe layer is difficult because SiGe alloys have different lattice constants from those of the common Si wafers, which leads to a high density of defects, including dislocations, micro-twins, cracks, and delaminations. This innovation utilizes newly developed rhombohedral epitaxy of cubic semiconductors on trigonal substrates in order to solve the lattice mismatch problem of SiGe by using trigonal single crystals like sapphire (Al2O3) as substrate to give a unique growth-orientation to the SiGe layer, which is automatically controlled at the interface upon sapphire (0001). This technology is different from previous silicon on insulator (SOI) or SGOI (SiGe on insulator) technologies that use amorphous SiO2 as the growth plane. A cubic semiconductor crystal is a special case of a rhombohedron with the inter-planar angle, alpha = 90 deg. With a mathematical transformation, all rhombohedrons can be described by trigonal crystal lattice structures. Therefore, all cubic lattice constants and crystal planes (hkl) s can be transformed into those of trigonal crystal parameters. These unique alignments enable a new opportunity of perfect lattice matching conditions, which can eliminate misfit dislocations. Previously, these atomic alignments were thought to be impossible or very difficult. With the invention of a new x-ray diffraction measurement method here, growth of cubic semiconductors on trigonal crystals became possible. This epitaxy and lattice-matching condition can be applied not only to SiGe (111)/sapphire (0001) substrate relations, but also to other crystal structures and other materials, including similar crystal structures which have pointgroup rotational symmetries by 120 because the cubic (111) direction has 120 rotational symmetry. The use of slightly miscut (less than
Robust matching algorithm for image mosaic
NASA Astrophysics Data System (ADS)
Zeng, Luan; Tan, Jiu-bin
2010-08-01
In order to improve the matching accuracy and the level of automation for image mosaic, a matching algorithm based on SIFT (Scale Invariant Feature Transform) features is proposed as detailed below. Firstly, according to the result of cursory comparison with the given basal matching threshold, the collection corresponding SIFT features which contains mismatch is obtained. Secondly, after calculating all the ratio of Euclidean distance from the closest neighbor to the distance of the second closest of corresponding features, we select the image coordinates of corresponding SIFT features with the first eight smallest ratios to solve the initial parameters of pin-hole camera model, and then calculate maximum error σ between transformation coordinates and original image coordinates of the eight corresponding features. Thirdly, calculating the scale of the largest original image coordinates of the eight corresponding features to the entire image size, the scale is regarded as control parameter k of matching error threshold. Finally, computing the difference of the transformation coordinates and the original image coordinates of all the features in the collection of features, deleting the corresponding features with difference larger than 3kσ. We can then obtain the exact collection of matching features to solve the parameters for pin-hole camera model. Experimental results indicate that the proposed method is stable and reliable in case of the image having some variation of view point, illumination, rotation and scale. This new method has been used to achieve an excellent matching accuracy on the experimental images. Moreover, the proposed method can be used to select the matching threshold of different images automatically without any manual intervention.
Nearly Perfect Fluidity in a High Temperature Superconductor
Rameau, J. D.; Reber, T. J.; Yang, H. -B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.
2014-10-13
Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.
Nearly Perfect Fluidity in a High Temperature Superconductor
Rameau, J. D.; Reber, T. J.; Yang, H. -B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.
2014-10-13
Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature T_{c}.
Perfect function transfer in two and three dimensions without initialization
Wu Lianao; Byrd, Mark; Wang, Z. D.; Shao Bin
2010-11-15
We find analytic models that can perfectly transfer, without state initialization or remote collaboration, arbitrary functions in two- and three-dimensional interacting bosonic and fermionic networks. This provides for the possible experimental implementation of state transfer through bosonic or fermionic atoms trapped in optical lattices. A significant finding is that the state of a spin qubit can be perfectly transferred through a fermionic system. Families of Hamiltonians are described that are related to the linear models and that enable the perfect transfer of arbitrary functions. Furthermore, we propose methods for eliminating certain types of errors.
Metamaterial perfect absorber based on artificial dielectric "atoms".
Liu, Xiaoming; Bi, Ke; Li, Bo; Zhao, Qian; Zhou, Ji
2016-09-01
In this work, we numerically designed and then experimentally verified a metamaterial perfect absorber based on artificial dielectric "atoms". This metamaterial absorber is composed of dielectric ceramic material (SrTiO_{3}) "atoms" embedded in a background matrix on a metal plate. The dielectric "atoms" couple strongly to the incident electric and magnetic fields at the Mie resonance mode, leading to the narrow perfect absorption band with simulated and experimental absorptivities of 99% and 98.5% at 8.96 GHz, respectively. The designed metamaterial perfect absorber is polarization insensitive and can operate in wide angle incidence. PMID:27607650
Ultra-broadband perfect cross polarization conversion metasurface
NASA Astrophysics Data System (ADS)
Dong, Guoxiang; Shi, Hongyu; Xia, Song; Zhang, Anxue; Xu, Zhuo; Wei, Xiaoyong
2016-04-01
We propose a metasurface with multiple plasmon resonances that achieves an ultra-broadband perfect cross polarization conversion. The metasurface is composed of an array of unit resonators, three plasmon resonances are excited in the unit resonator, which leads to an ultra-broadband perfect cross polarization conversion. The cross polarization conversion efficiency is higher than 99%, and the bandwidth of the converter is 53.7% of the central wavelength. Both numerical and experimental results were used to validate the ultra-broadband perfect cross polarization converter presented here.
Carrier mobility and crystal perfection of tetracene thin film FET
NASA Astrophysics Data System (ADS)
Moriguchi, N.; Nishikawa, T.; Anezaki, T.; Unno, A.; Tachibana, M.; Kojima, K.
2006-04-01
It is well-known that the carrier mobility of an organic field effect semiconductor (FET) depended on the crystal quality and/or the crystal perfection of the organic thin films [T.W. Kelly, D.V. Muyres, P.F. Baude, T.P. Smith, T.D. Jones, Mater. Res. Soc. Symp. Proc. 771 (2003) L6.5.1; D.J. Gundlach, J.A. Nichols, L. Zhou, T.N. Jackson, Appl. Phys. Lett. 80 (2002) 2925; H.K. Lauk, M. Halik, U. Zschieschang, G. Schmid, W. Radlik, J. Appl. Phys. 92 (2002) 5259; M. Shtein, J. Mapel, J.B. Benziger, S.R. Forrest, Appl. Phys. Lett. 81 (2002) 268; D. Knipp, R.A. Street, A.R. Volkel, Appl. Phys. Lett. 82 (2003) 3907; R. Ruiz, A.C. Mayer, G.G. Malliaras, Appl. Phys. Lett. 85 (2004) 4926; R.W.I. de Boer, M.E. Gershenson, A.F. Morpurgo, V. Podzorov, Phys. Stat. Sol. A 201 (2004) 1031]. To improve the crystal quality of the thin film many efforts were made. One of the important improvements was the surface treatment of the substrate. The tetracene thin film FET (top contact structure) was fabricated using the substrate, which was coated by a spin-coating method with a 0.1% poly α-methylstyrene (AMS) solution. The crystal quality was improved by this treatment so that the carrier mobility was higher than that of non-treatment. The maximum mobility of the AMS-treated sample was obtained to be 0.12 cm 2/V s.
ERIC Educational Resources Information Center
Snyder, Frank J.; Vuchinich, Samuel; Acock, Alan; Washburn, Isaac J.; Flay, Brian R.
2012-01-01
Background: School safety and quality affect student learning and success. This study examined the effects of a comprehensive elementary school-wide social-emotional and character education program, Positive Action, on teacher, parent, and student perceptions of school safety and quality utilizing a matched-pair, cluster-randomized, controlled…
High performance projectile seal development for non perfect railgun bores
Wolfe, T.R.; Vine, F.E. Le; Riedy, P.E.; Panlasigui, A.; Hawke, R.S.; Susoeff, A.R.
1997-01-01
The sealing of high pressure gas behind an accelerating projectile has been developed over centuries of use in conventional guns and cannons. The principal concern was propulsion efficiency and trajectory accuracy and repeatability. The development of guns for use as high pressure equation-of-state (EOS) research tools, increased the importance of better seals to prevent gas leakage from interfering with the experimental targets. The development of plasma driven railguns has further increased the need for higher quality seals to prevent gas and plasma blow-by. This paper summarizes more than a decade of effort to meet these increased requirements. In small bore railguns, the first improvement was prompted by the need to contain the propulsive plasma behind the projectile to avoid the initiation of current conducting paths in front of the projectile. The second major requirements arose from the development of a railgun to serve as an EOS tool where it was necessary to maintain an evacuated region in front of the projectile throughout the acceleration process. More recently, the techniques developed for the small bore guns have been applied to large bore railguns and electro-thermal chemical guns in order to maximize their propulsion efficiency. Furthermore, large bore railguns are often less rigid and less straight than conventional homogeneous material guns. Hence, techniques to maintain seals in non perfect, non homogeneous material launchers have been developed and are included in this paper.
Perfect imaging with positive refraction in three dimensions
Leonhardt, Ulf; Philbin, Thomas G.
2010-01-15
Maxwell's fish eye has been known to be a perfect lens within the validity range of ray optics since 1854. Solving Maxwell's equations, we show that the fish-eye lens in three dimensions has unlimited resolution for electromagnetic waves.
Senseless demolition in progress, showing destruction of perfectly decent and ...
Senseless demolition in progress, showing destruction of perfectly decent and recyclable mill building. Problem exacerbated by high value of scrap iron. - Phoenix Iron Company, Rolling Mill, North of French Creek, west of Fairview Avenue, Phoenixville, Chester County, PA
New exact perfect fluid solutions of Einstein's equations. II
NASA Astrophysics Data System (ADS)
Uggla, Claes; Rosquist, Kjell
1990-12-01
A family of new spatially homogeneous Bianchi type VIh perfect fluid solutions of the Einstein equations is presented. The fluid flow is orthogonal to the spatially homogeneous hypersurfaces, and the pressure is proportional to the energy density.
Perfection and the Bomb: Nuclear Weapons, Teleology, and Motives.
ERIC Educational Resources Information Center
Brummett, Barry
1989-01-01
Uses Kenneth Burke's theory of perfection to explore the vocabularies of nuclear weapons in United States public discourse and how "the Bomb" as a God term has gained imbalanced ascendancy in centers of power. (MS)
Perfect absorbers on curved surfaces and their potential applications.
Alaee, Rasoul; Menzel, Christoph; Rockstuhl, Carsten; Lederer, Falk
2012-07-30
Recently perfect metamaterial absorbers triggered some fascination since they permit the observation of an extreme interaction of light with a nanostructured thin film. For the first time we evaluate here the functionality of such perfect absorbers if they are applied on curved surfaces. We probe their optical response and discuss potential novel applications. Examples are the complete suppression of back-scattered light from the covered objects, rendering it cloaked in reflection, and their action as optical black holes. PMID:23038388
Picture Perfect: Document What You Do.
ERIC Educational Resources Information Center
Grothe, Mark
1996-01-01
Incorporating photographs into reports or promotional materials is an effective means of communicating needs and activities of the library media center. Provides techniques on how to improve picture taking with a standard camera. Discusses photo composition, positioning subjects, photographing reflective objects, lighting and focus tips,…
The Perfect Place for Learning Success.
ERIC Educational Resources Information Center
Tally-Foos, Kay
1989-01-01
Describes symptoms of learning disabled (LD) children and describes often-associated affects of learning disabilities on child's social skills. Recommends residential camp setting for LD children, suggesting the "learn-by-doing" environment helps them overcome challenges and to improve self esteem. Offers tips for designing LD camp programs. (TES)
Bilingual Education and Telecommunications: A Perfect Fit.
ERIC Educational Resources Information Center
Sayers, Dennis; Brown, Kristin
1987-01-01
Describes Project Orillas, a telecommunications network designed to improve the writing skills of bilingual and foreign language students studying English and Spanish in Mexico, Puerto Rico, and the United States. The electronic bulletin board system used for communication is explained and guidelines for joining the network are included. (LRW)
INFOODS guidelines for food matching
Technology Transfer Automated Retrieval System (TEKTRAN)
It is necessary to match food consumption data with food composition data in order to calculate estimates of nutrient intakes and dietary exposure. This can be done manually or through an automated system. As food matching procedures are key to obtaining high quality estimations of nutrient intake...
Donor-recipient matching: myths and realities.
Briceño, Javier; Ciria, Ruben; de la Mata, Manuel
2013-04-01
Liver transplant outcomes keep improving, with refinements of surgical technique, immunosuppression and post-transplant care. However, these excellent results and the limited number of organs available have led to an increasing number of potential recipients with end-stage liver disease worldwide. Deaths on waiting lists have led liver transplant teams maximize every organ offered and used in terms of pre and post-transplant benefit. Donor-recipient (D-R) matching could be defined as the technique to check D-R pairs adequately associated by the presence of the constituents of some patterns from donor and patient variables. D-R matching has been strongly analysed and policies in donor allocation have tried to maximize organ utilization whilst still protecting individual interests. However, D-R matching has been written through trial and error and the development of each new score has been followed by strong discrepancies and controversies. Current allocation systems are based on isolated or combined donor or recipient characteristics. This review intends to analyze current knowledge about D-R matching methods, focusing on three main categories: patient-based policies, donor-based policies and combined donor-recipient systems. All of them lay on three mainstays that support three different concepts of D-R matching: prioritarianism (favouring the worst-off), utilitarianism (maximising total benefit) and social benefit (cost-effectiveness). All of them, with their pros and cons, offer an exciting controversial topic to be discussed. All of them together define D-R matching today, turning into myth what we considered a reality in the past. PMID:23104164
Exciton Transport and Perfect Coulomb Drag
NASA Astrophysics Data System (ADS)
Nandi, Debaleena
2013-03-01
Exciton condensation is realized in closely-spaced bilayer quantum Hall systems at νT = 1 when the total density in the two 2D electron layers matches the Landau level degeneracy. In this state, electrons in one layer become tightly bound to holes in the other layer, forming a condensate similar to the Cooper pairs in a superconductor. Being charge neutral, these excitons ought to be free to move throughout the bulk of the quantum Hall fluid. One therefore expects that electron current driven in one layer would spontaneously generate a ``hole'' current in the other layer, even in the otherwise insulating bulk of the 2D system. We demonstrate precisely this effect, using a Corbino geometry to defeat edge state transport. Our sample contains two essentially identical two-dimensional electron systems (2DES) in GaAs quantum wells separated by a thin AlGaAs barrier. It is patterned into an annulus with arms protruding from each rim that provide contact to each 2DES separately. A current drag geometry is realized by applying a drive voltage between the outer and inner rim on one 2DES layer while the two rims on the opposite layer are connected together in a closed loop. There is no direct electrical connection between the two layers. At νT = 1 the bulk of the Corbino annulus becomes insulating owing to the quantum Hall gap and net charge transport across the bulk is suppressed. Nevertheless, we find that in the drag geometry appreciable currents do flow in each layer. These currents are almost exactly equal magnitude but, crucially, flow in opposite directions. This phenomenon reflects exciton transport within the νT = 1 condensate, rather than its quasiparticle excitations. We find that quasiparticle transport competes with exciton transport at elevated temperatures, drive levels, and layer separations. This work represents a collaboration with A.D.K. Finck, J.P. Eisenstein, L.N. Pfeiffer and K.W. West. This work is supported by the NSF under grant DMR-1003080.
[Bioresorbable scaffolds - nobody is perfect (yet)].
Alibegovic Zaza, J; Zaza, S
2015-03-01
The new generation drug eluting stents have improved the results of coronary angioplasty by reducing the rate of instent restenosis and stent thrombosis compared to earlier devices, due to the thinner stent struts and improved or bioresorbable polymers. But permanent metallic stent struts may have some long term harmful effects such as inducing late thrombosis, neoatherosclerosis, restenosis and also impairing vasomotion and endothelial function. This was the rationale for introducing bioresorbable stents which offer radial support to the artery during the period needed (scaffolding) and then disappear, (liberating the vessels and restoring its physiological vasomotion. New randomized studies have shown their non-inferiority compared to new generation metallic drug eluting stents, but there are still some challenges to be overcome. PMID:25924249
Matching by adjustment: if x matches y, does y match x?
Dzhafarov, Ehtibar; Perry, Lacey
2010-01-01
When dealing with pairwise comparisons of stimuli in two fixed observation areas (e.g., one stimulus on the left, one on the right), we say that the stimulus space is regular well-matched if (1) every stimulus is matched by some stimulus in another observation area, and this matching stimulus is determined uniquely up to matching equivalence (two stimuli being equivalent if they always match or do not match any stimulus together); and (2) if a stimulus is matched by another stimulus then it matches it. The regular well-matchedness property has non-trivial consequences for several issues, ranging from the ancient "sorites" paradox to "probability-distance hypothesis" to modeling of discrimination probabilities by means of Thurstonian-type models. We have tested the regular well-matchedness hypothesis for locations of two dots within two side-by-side circles, and for two side-by-side "flower-like" shapes obtained by superposition of two cosine waves with fixed frequencies in polar coordinates. In the location experiment the two coordinates of the dot in one circle were adjusted to match the location of the dot in another circle. In the shape experiment the two cosine amplitudes of one shape were adjusted to match the other shape. The adjustments on the left and on the right alternated in long series according to the "ping-pong" matching scheme developed in Dzhafarov (2006b, J. Math. Psychol., 50, 74-93). The results have been found to be in a good agreement with the regular well-matchedness hypothesis. PMID:21833195
Final report, DOE/industry matching grant
Kumar, Arvind S.
2003-02-25
The Department of Energy/Industry Matching Grant was used to help improve nuclear engineering and science education at the University of Missouri-Rolla. The funds helped in the areas of recruitment and retention. Funds allowed the department to give scholarships to over 100 students (names included). Funds were also used for equipment upgrade and research, including two computers with peripherals, two NaI detectors, and a thermoluminescent dosimeter.
An Integrated Method for GML Application Schema Match
NASA Astrophysics Data System (ADS)
Li, Chao; Zeng, Xiao; Xiong, Zhang
GML has been a standard in geographical information area for enhancing the interoperability of various GIS systems for data mining. In order to share geography information based on GML, problems in application schema match need to be overcome first. This paper introduces an integrated multi-strategy approach on GML application schema match. It combines existing scheme match algorithm with GML3.0 application schema. Firstly, it transforms the input GML application schemas into a GSTree according to linguistic-based and constraint-based match rules. Similarity between two elements is calculated trough different rules separately, and merged into element-level similarity. Secondly, the element-level similarity is rectified by a structure-level match algorithm based on similarity flooding. Finally, the mapping table of GML application schema elements is obtained. The experiment result shows that the approach can effectively discovery the similarity of schema elements, and improve the match results with a high degree of accuracy.
Structural color printing based on plasmonic metasurfaces of perfect light absorption
NASA Astrophysics Data System (ADS)
Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong
2015-06-01
Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.
Structural color printing based on plasmonic metasurfaces of perfect light absorption
Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong
2015-01-01
Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage. PMID:26047486
Structural color printing based on plasmonic metasurfaces of perfect light absorption
Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong
2015-06-05
Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.
Code of Federal Regulations, 2014 CFR
2014-10-01
...) Wax “Vesta” matches are matches that can be ignited by friction either on a prepared surface or on a solid surface. (c) Safety matches and wax “Vesta” matches must be tightly packed in securely closed... packaging with any material other than safety matches or wax “Vesta” matches, which must be packed...
Code of Federal Regulations, 2011 CFR
2011-10-01
...) Wax “Vesta” matches are matches that can be ignited by friction either on a prepared surface or on a solid surface. (c) Safety matches and wax “Vesta” matches must be tightly packed in securely closed... packaging with any material other than safety matches or wax “Vesta” matches, which must be packed...
Code of Federal Regulations, 2012 CFR
2012-10-01
...) Wax “Vesta” matches are matches that can be ignited by friction either on a prepared surface or on a solid surface. (c) Safety matches and wax “Vesta” matches must be tightly packed in securely closed... packaging with any material other than safety matches or wax “Vesta” matches, which must be packed...
Code of Federal Regulations, 2010 CFR
2010-10-01
...) Wax “Vesta” matches are matches that can be ignited by friction either on a prepared surface or on a solid surface. (c) Safety matches and wax “Vesta” matches must be tightly packed in securely closed... packaging with any material other than safety matches or wax “Vesta” matches, which must be packed...
Code of Federal Regulations, 2013 CFR
2013-10-01
...) Wax “Vesta” matches are matches that can be ignited by friction either on a prepared surface or on a solid surface. (c) Safety matches and wax “Vesta” matches must be tightly packed in securely closed... packaging with any material other than safety matches or wax “Vesta” matches, which must be packed...
Biomechanics and biocompatibility of the perfect conduit—can we build one?
Ng, Martin K.C.; Bannon, Paul G.
2013-01-01
No currently available conduit meets the criteria for an ideal coronary artery bypass graft. The perfect conduit would combine the availability and complication-free harvest of a synthetic vessel with the long-term patency performance of the internal mammary artery. However, current polymer conduits suffer from inelastic mechanical properties and especially poor surface biocompatibility, resulting in early loss of patency as a coronary graft. Approaches to manufacture an improved conduit using new polymers or polymer surfaces, acellular matrices, or cellular constructs have to date failed to achieve a commercially successful alternative. Elastin, by mimicking the native extracellular environment as well as providing elasticity, provides the ‘missing link’ in vascular conduit design and brings new hope for realization of the perfect conduit. PMID:23977620
Biomechanics and biocompatibility of the perfect conduit-can we build one?
Byrom, Michael J; Ng, Martin K C; Bannon, Paul G
2013-07-01
No currently available conduit meets the criteria for an ideal coronary artery bypass graft. The perfect conduit would combine the availability and complication-free harvest of a synthetic vessel with the long-term patency performance of the internal mammary artery. However, current polymer conduits suffer from inelastic mechanical properties and especially poor surface biocompatibility, resulting in early loss of patency as a coronary graft. Approaches to manufacture an improved conduit using new polymers or polymer surfaces, acellular matrices, or cellular constructs have to date failed to achieve a commercially successful alternative. Elastin, by mimicking the native extracellular environment as well as providing elasticity, provides the 'missing link' in vascular conduit design and brings new hope for realization of the perfect conduit. PMID:23977620
Evaluation of matching cost on the ISPRS stereo matching benchmark
NASA Astrophysics Data System (ADS)
Yue, Qingxing; Tang, Xinming; Gao, Xiaoming
2015-12-01
In this paper we evaluated several typical matching costs including CENSUS, mutual information (MI) and the normalized cross correlation using the ISPRS Stereo Matching Benchmark datasets for DSM generation by stereo matching. Two kinds of global optimization algorithms including semi-global matching (SGM) and graph cuts (GC) were used as optimization method. We used a sub-pixel method to obtain more accurate MI lookup table and a sub-pixel method was also used when computing cost by MI lookup table. MI itself is sensitive to partial radiation differences. So we used a kind of cost combined MI and CENSUS. After DSM generation, the deviation data between the generated DSM and Lidar was statistics out to compute the mean deviation (Mean), the median deviation (Med), the standard deviation (Stdev), the normalized median absolute deviation (NMAD), the percentage of deviation in tolerance etc., which were used to evaluate the accuracy of DSM generated from different cost.
Son, S. F.; Hiskey, M. A.; Naud, D.; Busse, J. R.; Asay, B. W.
2002-01-01
Electric matches are used in pyrotechnics to initiate devices electrically rather than by burning fuses. Fuses have the disadvantage of burning with a long delay before igniting a pyrotechnic device, while electric matches can instantaneously fire a device at a user's command. In addition, electric matches can be fired remotely at a safe distance. Unfortunately, most current commercial electric match compositions contain lead as thiocyanate, nitroresorcinate or tetroxide, which when burned, produces lead-containing smoke. This lead pollutant presents environmental exposure problems to cast, crew, and audience. The reason that these lead containing compounds are used as electric match compositions is that these mixtures have the required thermal stability, yet are simultaneously able to be initiated reliably by a very small thermal stimulus. A possible alternative to lead-containing compounds is nanoscale thermite materials (metastable intermolecular composites or MIC). These superthermite materials can be formulated to be extremely spark sensitive with tunable reaction rate and yield high temperature products. We have formulated and manufactured lead-free electric matches based on nanoscale Al/MoO{sub 3} mixtures. We have determined that these matches fire reliably and to consistently ignite a sample of black powder. Initial safety, ageing and performance results are presented in this paper.
MATCHING IN INFORMAL FINANCIAL INSTITUTIONS
Eeckhout, Jan; Munshi, Kaivan
2013-01-01
This paper analyzes an informal financial institution that brings heterogeneous agents together in groups. We analyze decentralized matching into these groups, and the equilibrium composition of participants that consequently arises. We find that participants sort remarkably well across the competing groups, and that they re-sort immediately following an unexpected exogenous regulatory change. These findings suggest that the competitive matching model might have applicability and bite in other settings where matching is an important equilibrium phenomenon. (JEL: O12, O17, G20, D40) PMID:24027491
Perfect World, Perfect Societies - The Persistent Goal of Utopia in Human Spaceflight
NASA Astrophysics Data System (ADS)
Launius, R. D.
This essay sets about the task of exploring three basic aspects of the persistent goal of Utopia in human spaceflight. First, after briefly considering the rise of spaceflight in the United States, this essay will discuss the rise of a zealous pro-space movement in the 1970s and the resulting efforts to justify space exploration using a range of arguments that at their base contain a strong element of utopianism. Second, this paper shall investigate the radical ideas of spaceflight utopianism contained in the work of Gerard K. O'Neill and extending to the present with advocates such as Robert Zubrin. Finally, this essay will explore flaws in the utopian impulse in favor of space exploration. Like all works of advocacy, those who seek to “sell” spaceflight as a positive good overstate their cases. Clearly the radical utopian ideal of creating a perfect society has numerous effective detractors and may be debunked using any number of methodologies: history, psychology, economics, political theory, and technological hubris. At the same time, spaceflight advocates have some untapped aspects to their utopian arguments that would greatly strengthen their position should they effectively articulate them.
Practice makes perfect in memory recall.
Romani, Sandro; Katkov, Mikhail; Tsodyks, Misha
2016-04-01
A large variability in performance is observed when participants recall briefly presented lists of words. The sources of such variability are not known. Our analysis of a large data set of free recall revealed a small fraction of participants that reached an extremely high performance, including many trials with the recall of complete lists. Moreover, some of them developed a number of consistent input-position-dependent recall strategies, in particular recalling words consecutively ("chaining") or in groups of consecutively presented words ("chunking"). The time course of acquisition and particular choice of positional grouping were variable among participants. Our results show that acquiring positional strategies plays a crucial role in improvement of recall performance. PMID:26980785
Class of near-perfect coded apertures
NASA Technical Reports Server (NTRS)
Cannon, T. M.; Fenimore, E. E.
1977-01-01
Coded aperture imaging of gamma ray sources has long promised an improvement in the sensitivity of various detector systems. The promise has remained largely unfulfilled, however, for either one of two reasons. First, the encoding/decoding method produces artifacts, which even in the absence of quantum noise, restrict the quality of the reconstructed image. This is true of most correlation-type methods. Second, if the decoding procedure is of the deconvolution variety, small terms in the transfer function of the aperture can lead to excessive noise in the reconstructed image. It is proposed to circumvent both of these problems by use of a uniformly redundant array (URA) as the coded aperture in conjunction with a special correlation decoding method.
New Effective Multithreaded Matching Algorithms
Manne, Fredrik; Halappanavar, Mahantesh
2014-05-19
Matching is an important combinatorial problem with a number of applications in areas such as community detection, sparse linear algebra, and network alignment. Since computing optimal matchings can be very time consuming, several fast approximation algorithms, both sequential and parallel, have been suggested. Common to the algorithms giving the best solutions is that they tend to be sequential by nature, while algorithms more suitable for parallel computation give solutions of less quality. We present a new simple 1 2 -approximation algorithm for the weighted matching problem. This algorithm is both faster than any other suggested sequential 1 2 -approximation algorithm on almost all inputs and also scales better than previous multithreaded algorithms. We further extend this to a general scalable multithreaded algorithm that computes matchings of weight comparable with the best sequential algorithms. The performance of the suggested algorithms is documented through extensive experiments on different multithreaded architectures.
Refractive surgery: the future of perfect vision?
Fong, C S
2007-08-01
The history of refractive eye surgery is recent, but has seen rapid advancement. Older technologies, such as radial keratectomy, had the problem of overcorrection and epithelial complications. Newer technologies, such as photorefractive keratectomy, laser-assisted in-situ keratomileusis (LASIK) and laser-assisted subepithelial keratomileusis (LASEK), which require the use of laser, has revolutionised eye surgery. However, there are complications, such as corneal hazing, postoperative pain, regression, and poorer correction for high myopes. If not contraindicated, wavefront analysis and femtosecond laser are useful adjuncts to laser photoablation for better visual results. Wavefront analysis improves the precision of laser photoablation by measuring the individual's wavefront aberrations, while femtosecond laser offers an instrument-free means of creating the corneal hinge. Lastly, implantation of intraocular lenses, with or without extraction of the crystalline lens, provides an alternative to laser photoablation for the treatment of high myopia. Clear lens exchange offers refractive correction to presbyopes and people with cataracts. However, complications, such as endothelial cell loss, cataract formation and retinal detachment, exist. In conclusion, refractive eye surgery provides an alternative to wearing spectacles or contact lenses. However, potential patients must be warned of the complications and long-term effects on the eyes. PMID:17657376
Perfect transfer of arbitrary states in quantum spin networks
Christandl, Matthias; Kay, Alastair; Datta, Nilanjana; Dorlas, Tony C.; Ekert, Artur; Landahl, Andrew J.
2005-03-01
We propose a class of qubit networks that admit perfect state transfer of any two-dimensional quantum state in a fixed period of time. We further show that such networks can distribute arbitrary entangled states between two distant parties, and can, by using such systems in parallel, transmit the higher-dimensional systems states across the network. Unlike many other schemes for quantum computation and communication, these networks do not require qubit couplings to be switched on and off. When restricted to N-qubit spin networks of identical qubit couplings, we show that 2 log{sub 3}N is the maximal perfect communication distance for hypercube geometries. Moreover, if one allows fixed but different couplings between the qubits then perfect state transfer can be achieved over arbitrarily long distances in a linear chain. This paper expands and extends the work done by Christandl et al., Phys. Rev. Lett. 92, 187902 (2004)
Large-Scale All-Dielectric Metamaterial Perfect Reflectors
Moitra, Parikshit; Slovick, Brian A.; li, Wei; Kravchencko, Ivan I.; Briggs, Dayrl P.; Krishnamurthy, S.; Valentine, Jason
2015-05-08
All-dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. In this paper, we take advantage of the low absorption loss as well as the simple unit cell geometry to demonstrate large-scale (centimeter-sized) all-dielectric metamaterial perfect reflectors made from silicon cylinder resonators. These perfect reflectors, operating in the telecommunications band, were fabricated using self-assembly based nanosphere lithography. In spite of the disorder originating from the self-assembly process, the average reflectance of the metamaterial perfect reflectors is 99.7% at 1530 nm, surpassing the reflectance of metallic mirrors. Moreover, the spectral separation of the electric and magnetic resonances can be chosen to achieve the required reflection bandwidth while maintaining a high tolerance to disorder. Finally, the scalability of this design could lead to new avenues of manipulating light for low-loss and large-area photonic applications.
Progress toward high-Q perfect absorption: A Fano antilaser
NASA Astrophysics Data System (ADS)
Yu, Sunkyu; Piao, Xianji; Hong, Jiho; Park, Namkyoo
2015-07-01
Here we propose a route to the high-Q perfect absorption of light by introducing the concept of a Fano antilaser. Based on the drastic spectral variation of the optical phase in a Fano-resonant system, a spectral singularity for scatter-free perfect absorption can be achieved with an order of magnitude smaller material loss. By applying temporal coupled mode theory to a Fano-resonant waveguide platform, we reveal that the required material loss and following absorption Q factor are ultimately determined by the degree of Fano spectral asymmetry. The feasibility of the Fano antilaser is confirmed using a photonic crystal platform, to demonstrate spatiospectrally selective heating. Our results utilizing the phase-dependent control of device bandwidths derive a counterintuitive realization of high-Q perfect conversion of light into internal energy, and thus pave the way for a new regime of absorption-based devices, including switches, sensors, thermal imaging, and optothermal emitters.
Large-Scale All-Dielectric Metamaterial Perfect Reflectors
Moitra, Parikshit; Slovick, Brian A.; li, Wei; Kravchencko, Ivan I.; Briggs, Dayrl P.; Krishnamurthy, S.; Valentine, Jason
2015-05-08
All-dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. In this paper, we take advantage of the low absorption loss as well as the simple unit cell geometry to demonstrate large-scale (centimeter-sized) all-dielectric metamaterial perfect reflectors made from silicon cylinder resonators. These perfect reflectors, operating in the telecommunications band, were fabricated using self-assembly based nanosphere lithography. In spite of the disorder originating from the self-assembly process, the average reflectance of the metamaterial perfect reflectors is 99.7% at 1530 nm, surpassing the reflectance of metallic mirrors. Moreover, the spectral separation of the electric and magnetic resonances canmore » be chosen to achieve the required reflection bandwidth while maintaining a high tolerance to disorder. Finally, the scalability of this design could lead to new avenues of manipulating light for low-loss and large-area photonic applications.« less
Experimental perfect state transfer of an entangled photonic qubit
NASA Astrophysics Data System (ADS)
Chapman, Robert J.; Santandrea, Matteo; Huang, Zixin; Corrielli, Giacomo; Crespi, Andrea; Yung, Man-Hong; Osellame, Roberto; Peruzzo, Alberto
2016-04-01
The transfer of data is a fundamental task in information systems. Microprocessors contain dedicated data buses that transmit bits across different locations and implement sophisticated routing protocols. Transferring quantum information with high fidelity is a challenging task, due to the intrinsic fragility of quantum states. Here we report on the implementation of the perfect state transfer protocol applied to a photonic qubit entangled with another qubit at a different location. On a single device we perform three routing procedures on entangled states, preserving the encoded quantum state with an average fidelity of 97.1%, measuring in the coincidence basis. Our protocol extends the regular perfect state transfer by maintaining quantum information encoded in the polarization state of the photonic qubit. Our results demonstrate the key principle of perfect state transfer, opening a route towards data transfer for quantum computing systems.
Experimental perfect state transfer of an entangled photonic qubit.
Chapman, Robert J; Santandrea, Matteo; Huang, Zixin; Corrielli, Giacomo; Crespi, Andrea; Yung, Man-Hong; Osellame, Roberto; Peruzzo, Alberto
2016-01-01
The transfer of data is a fundamental task in information systems. Microprocessors contain dedicated data buses that transmit bits across different locations and implement sophisticated routing protocols. Transferring quantum information with high fidelity is a challenging task, due to the intrinsic fragility of quantum states. Here we report on the implementation of the perfect state transfer protocol applied to a photonic qubit entangled with another qubit at a different location. On a single device we perform three routing procedures on entangled states, preserving the encoded quantum state with an average fidelity of 97.1%, measuring in the coincidence basis. Our protocol extends the regular perfect state transfer by maintaining quantum information encoded in the polarization state of the photonic qubit. Our results demonstrate the key principle of perfect state transfer, opening a route towards data transfer for quantum computing systems. PMID:27088483
Experimental perfect state transfer of an entangled photonic qubit
Chapman, Robert J.; Santandrea, Matteo; Huang, Zixin; Corrielli, Giacomo; Crespi, Andrea; Yung, Man-Hong; Osellame, Roberto; Peruzzo, Alberto
2016-01-01
The transfer of data is a fundamental task in information systems. Microprocessors contain dedicated data buses that transmit bits across different locations and implement sophisticated routing protocols. Transferring quantum information with high fidelity is a challenging task, due to the intrinsic fragility of quantum states. Here we report on the implementation of the perfect state transfer protocol applied to a photonic qubit entangled with another qubit at a different location. On a single device we perform three routing procedures on entangled states, preserving the encoded quantum state with an average fidelity of 97.1%, measuring in the coincidence basis. Our protocol extends the regular perfect state transfer by maintaining quantum information encoded in the polarization state of the photonic qubit. Our results demonstrate the key principle of perfect state transfer, opening a route towards data transfer for quantum computing systems. PMID:27088483
Dual band metamaterial perfect absorber based on Mie resonances
NASA Astrophysics Data System (ADS)
Liu, Xiaoming; Lan, Chuwen; Bi, Ke; Li, Bo; Zhao, Qian; Zhou, Ji
2016-08-01
We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric "atom" with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric "atom" and copper plate. Mie resonances of dielectric "atom" provide a simple way to design metamaterial perfect absorbers with high symmetry.
Dual band metamaterial perfect absorber based on artificial dielectric "molecules".
Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhao, Qian; Zhou, Ji
2016-01-01
Dual band metamaterial perfect absorbers with two absorption bands are highly desirable because of their potential application areas such as detectors, transceiver system, and spectroscopic imagers. However, most of these dual band metamaterial absorbers proposed were based on resonances of metal patterns. Here, we numerically and experimentally demonstrate a dual band metamaterial perfect absorber composed of artificial dielectric "molecules" with high symmetry. The artificial dielectric "molecule" consists of four "atoms" of two different sizes corresponding to two absorption bands with near unity absorptivity. Numerical and experimental absorptivity verify that the dual-band metamaterial absorber is polarization insensitive and can operate in wide-angle incidence. PMID:27406699
Cosmological perturbations of a perfect fluid and noncommutative variables
De Felice, Antonio; Gerard, Jean-Marc; Suyama, Teruaki
2010-03-15
We describe the linear cosmological perturbations of a perfect fluid at the level of an action, providing thus an alternative to the standard approach based only on the equations of motion. This action is suited not only to perfect fluids with a barotropic equation of state, but also to those for which the pressure depends on two thermodynamical variables. By quantizing the system we find that (1) some perturbation fields exhibit a noncommutativity quite analogous to the one observed for a charged particle moving in a strong magnetic field, (2) local curvature and pressure perturbations cannot be measured simultaneously, (3) ghosts appear if the null energy condition is violated.
NASA Astrophysics Data System (ADS)
Chen, Menglin L. N.; Jiang, Li Jun; Sha, Wei E. I.
2016-02-01
Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect electric conductor-perfect magnetic conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation.
Design of a perfect balance system for active upper-extremity exoskeletons.
Smith, Richard L; Lobo-Prat, Joan; van der Kooij, Herman; Stienen, Arno H A
2013-06-01
Passive gravity compensation in exoskeletons significantly reduces the amount of torque and energy needed from the actuators. So far, no design has been able to achieve perfect balance without compromising the exoskeleton characteristics. Here we propose a novel design that integrates an existing statically-balanced mechanism with two springs and four degrees of freedom into a general-purpose exoskeleton design, that can support any percentage of the combined weight of exoskeleton and arm. As it allows for three rotational degrees of freedom at the shoulder and one at the elbow, it does not compromise exoskeleton characteristics and can be powered with any choice of passive or active actuation method. For instance, with this design a perfectly balanced exoskeleton design with inherently safe, passive actuators on each joint axis becomes possible. The potential reduction in required actuator torque, power and weight, simplification of control, improved dynamic performance, and increased safety margin, all while maintaining perfect balance, are the major advantages of the design, but the integrated systems does add a significant amount of complexity. Future integration in an actual exoskeleton should prove if this tradeoff is beneficial. PMID:24187195
Matched Peptides: Tuning Matched Molecular Pair Analysis for Biopharmaceutical Applications
2015-01-01
Biopharmaceuticals hold great promise for the future of drug discovery. Nevertheless, rational drug design strategies are mainly focused on the discovery of small synthetic molecules. Herein we present matched peptides, an innovative analysis technique for biological data related to peptide and protein sequences. It represents an extension of matched molecular pair analysis toward macromolecular sequence data and allows quantitative predictions of the effect of single amino acid substitutions on the basis of statistical data on known transformations. We demonstrate the application of matched peptides to a data set of major histocompatibility complex class II peptide ligands and discuss the trends captured with respect to classical quantitative structure–activity relationship approaches as well as structural aspects of the investigated protein–peptide interface. We expect our novel readily interpretable tool at the interface of cheminformatics and bioinformatics to support the rational design of biopharmaceuticals and give directions for further development of the presented methodology. PMID:26501781
The Perfective Past Tense in Greek as a Second Language
ERIC Educational Resources Information Center
Clahsen, Harald; Martzoukou, Maria; Stavrakaki, Stavroula
2010-01-01
This study reports results from four experiments investigating the perfective past tense of Greek in adult second language (L2) learners. The data come from L2 learners of Greek with intermediate to advanced L2 proficiency and different native language (L1) backgrounds, and L1 speakers of Greek. All participants were tested in both oral and…
Designing the Perfect Plant: Activities to Investigate Plant Ecology
ERIC Educational Resources Information Center
Lehnhoff, Erik; Woolbaugh, Walt; Rew, Lisa
2008-01-01
Plant ecology is an important subject that often receives little attention in middle school, as more time during science classes is devoted to plant biology. Therefore, the authors have developed a series of activities, including a card game--Designing the Perfect Plant--to introduce student's to plant ecology and the ecological trade offs…
Unity and Duality in Barack Obama's "A More Perfect Union"
ERIC Educational Resources Information Center
Terrill, Robert E.
2009-01-01
Faced with a racialized political crisis that threatened to derail his campaign to become the first African American president of the United States, Barack Obama delivered a speech on race titled "A More Perfect Union." He begins by portraying himself as an embodiment of double consciousness, but then invites his audience to share his doubled…
Overemphasis on Perfectly Competitive Markets in Microeconomics Principles Textbooks
ERIC Educational Resources Information Center
Hill, Roderick; Myatt, Anthony
2007-01-01
Microeconomic principles courses focus on perfectly competitive markets far more than other market structures. The authors examine five possible reasons for this but find none of them sufficiently compelling. They conclude that textbook authors should place more emphasis on how economists select appropriate models and test models' predictions…
Solution of mathematical programming formulations of subgame perfect equilibrium problems
Macal, C.M.; Hurter, A.P.
1992-02-12
Mathematical programming models have been developed to represent imperfectly competitive (oligopolistic) market structures and the interdependencies of decision-making units in establishing prices and production levels. The solution of these models represents an economic equilibrium. A subgame perfect equilibrium formulation explicitly considers that each agent`s strategies depend on the current state of the system; the state depends solely on previous decisions made by the economic agents. The structure of an industry-wide model that is formulated as a subgame perfect equilibrium problem is a matrix of simultaneous mathematical programming problems, where the rows represent time periods and the columns represent agents. This paper formally defines the subgame perfect equilibrium problem that includes mathematical programs for agent decision problems, and it characterizes the feasible space in a way that is conducive to the solution of the problem. The existence of equilibrium solutions on convex subspaces of the feasible region is proved, and this set is shown to contain the subgame perfect equilibrium solutions. A procedure for computing equilibrium solutions and systematically searching the subspaces is illustrated by a numerical example.
The Future for Higher Education: Sunrise or Perfect Storm?
ERIC Educational Resources Information Center
Hilton, James
2006-01-01
In today's knowledge economy, the role of higher education is being redefined--not simply tweaked and fine-tuned but, rather, fundamentally redefined. The author contends that there are at least two ways to frame this future for higher education. The first is to view it as a perfect storm, born from the convergence of numerous disruptive forces.…
Experimental realization of Coherent Perfect Rotation in TGG
NASA Astrophysics Data System (ADS)
Zhou, Chuanhong; Andrews, James; Petrus, Joshua; Crescimanno, Michael
2014-05-01
Coherent Perfect Rotation is the reversible generalization of the anti-laser process that can occur in optical systems with Faraday rotation. We describe the first experiment to verify CPR using a TGG resonator, and give an assessment of the experimentally achievable contrast ratio of the CPR resonance and remark on its utility in optical devices and related future experiments.
Computation of Thermally Perfect Oblique Shock Wave Properties
NASA Technical Reports Server (NTRS)
Tatum, Kenneth E.
1997-01-01
A set of compressible flow relations describing flow properties across oblique shock waves, derived for a thermally perfect, calorically imperfect gas, is applied within the existing thermally perfect gas (TPG) computer code. The relations are based upon the specific heat expressed as a polynomial function of temperature. The updated code produces tables of compressible flow properties of oblique shock waves, as well as the original properties of normal shock waves and basic isentropic flow, in a format similar to the tables for normal shock waves found in NACA Rep. 1135. The code results are validated in both the calorically perfect and the calorically imperfect, thermally perfect temperature regimes through comparisons with the theoretical methods of NACA Rep. 1135. The advantages of the TPG code for oblique shock wave calculations, as well as for the properties of isentropic flow and normal shock waves, are its ease of use and its applicability to any type of gas (monatomic, diatomic, triatomic, polyatomic, or any specified mixture thereof).
Blogs and Written Business Communication Courses: A Perfect Union
ERIC Educational Resources Information Center
Quible, Zane K.
2005-01-01
One of the newest Internet applications--the Weblog, or blog--is rapidly increasing in number as well as expanding in use. Blogs are used in various segments of society, including the business and educational worlds. They are a perfect fit for use in written business communication courses because of the ease with which writing examples…
Effective vibration isolation system for perfect-crystal neutron interferometry
Arthur, J.
1985-01-01
Perfect-crystal neutron interferometers are subject to degradation of their performance caused by vibrational accelerations. It is shown that the most seriously offending accelerations are rotational, and an effective and simple vibration isolation system that has been developed at the MIT Neutron Diffraction Laboratory is described.
Perfect Power Prototype for Illinois Institute of Technology
Shahidehpour, Mohammad
2014-09-30
Starting in October 2008, Illinois Institute of Technology (IIT), in collaboration with over 20 participating members, led an extensive effort to develop, demonstrate, promote, and commercialize a microgrid system and offer supporting technologies that will achieve Perfect Power at the main campus of IIT. A Perfect Power system, as defined by the Galvin Electricity Initiative (GEI), is a system that cannot fail to meet the electric needs of the individual end-user. The Principle Investigator of this Perfect Power project was Dr. Mohammad Shahidehpour, Director of the Robert W. Galvin Center for Electricity Innovation at IIT. There were six overall objectives of the Perfect Power project: (1) Demonstrate the higher reliability introduced by the microgrid system at IIT; (2) Demonstrate the economics of microgrid operations; (3) Allow for a decrease of fifty percent (50%) of grid electricity load; (4) Create a permanent twenty percent (20%) decrease in peak load from 2007 level; (5) Defer planned substation through load reduction; (6) Offer a distribution system design that can be replicated in urban communities.
Computation of Thermally Perfect Properties of Oblique Shock Waves
NASA Technical Reports Server (NTRS)
Tatum, Kenneth E.
1996-01-01
A set of compressible flow relations describing flow properties across oblique shock waves, derived for a thermally perfect, calorically imperfect gas, is applied within the existing thermally perfect gas (TPG) computer code. The relations are based upon a value of cp expressed as a polynomial function of temperature. The updated code produces tables of compressible flow properties of oblique shock waves, as well as the original properties of normal shock waves and basic isentropic flow, in a format similar to the tables for normal shock waves found in NACA Rep. 1135. The code results are validated in both the calorically perfect and the calorically imperfect, thermally perfect temperature regimes through comparisons with the theoretical methods of NACA Rep. 1135, and with a state-of-the-art computational fluid dynamics code. The advantages of the TPG code for oblique shock wave calculations, as well as for the properties of isentropic flow and normal shock waves, are its ease of use, and its applicability to any type of gas (monatomic, diatomic, triatomic, polyatomic, or any specified mixture thereof).
America's Perfect Storm: Three Forces Changing Our Nation's Future
ERIC Educational Resources Information Center
Kirsch, Irwin; Braun, Henry; Yamamoto, Kentaro; Sum, Andrew
2007-01-01
The authors offer the image of our nation as a nautical convoy. Some boats are large, well built, and able to ride out the heaviest of turbulent seas. Others are smaller, but still quite sturdy, and able to survive. Many however, are fragile, meagerly equipped, and easily capsized in rough waters. This convoy is in the midst of a perfect storm…
Inhomogeneous generalizations of Bianchi type VIh models with perfect fluid
NASA Astrophysics Data System (ADS)
Roy, S. R.; Prasad, A.
1991-07-01
Inhomogeneous universes admitting an Abelian G2 of isometry and filled with perfect fluid have been derived. These contain as special cases exact homogeneous universes of Bianchi type VIh. Many of these universes asymptotically tend to homogeneous Bianchi VIh universes. The models have been discussed for their physical and kinematical behaviors.
World Languages and International Education--Perfect Together
ERIC Educational Resources Information Center
Zeppieri, Roseanne; Russel, Priscilla
2008-01-01
Several decades ago, New Jersey adopted the slogan "New Jersey and You--perfect together!" A catchy phrase, the state used this for years to attract people to the state and to highlight all that this combination has to offer. When the International Education movement began to take hold in New Jersey a few years ago, the authors were charged with…
Perfect decoupling of linear systems with discrete parameter uncertainties
NASA Technical Reports Server (NTRS)
Dorato, P.; Wang, S.-H.; Asher, R.
1977-01-01
A design procedure based on Gilbert's decoupling parameters for determining a fixed state feedback control law which decouples a linear system with discrete parameter uncertainties is described. Perfect decoupling conditions are established which involve a test for the existence of a solution to a system of linear equations. An actual solution of the linear equations yields the decoupling control law.
Reprint Series: Prime Numbers and Perfect Numbers. RS-2.
ERIC Educational Resources Information Center
Schaaf, William L., Ed.
This is one in a series of SMSG supplementary and enrichment pamphlets for high school students. This series makes available expository articles which appeared in a variety of mathematical periodicals. Topics covered include: (1) the prime numbers; (2) mathematical sieves; (3) the factorgram; and (4) perfect numbers. (MP)
The Perfect Storm--Genetic Engineering, Science, and Ethics
ERIC Educational Resources Information Center
Rollin, Bernard E.
2014-01-01
Uncertainty about ethics has been a major factor in societal rejection of biotechnology. Six factors help create a societal "perfect storm" regarding ethics and biotechnology: Social demand for ethical discussion; societal scientific illiteracy; poor social understanding of ethics; a "Gresham's Law for Ethics;" Scientific…
The Perfect Storm—Genetic Engineering, Science, and Ethics
NASA Astrophysics Data System (ADS)
Rollin, Bernard E.
2012-07-01
Uncertainty about ethics has been a major factor in societal rejection of biotechnology. Six factors help create a societal "perfect storm" regarding ethics and biotechnology: Social demand for ethical discussion; societal scientific illiteracy; poor social understanding of ethics; a "Gresham's Law for Ethics;" Scientific Ideology; vested interests dominating ethical discussion. How this can be remedied is discussed.
Poor Textural Image Matching Based on Graph Theory
NASA Astrophysics Data System (ADS)
Chen, Shiyu; Yuan, Xiuxiao; Yuan, Wei; Cai, Yang
2016-06-01
Image matching lies at the heart of photogrammetry and computer vision. For poor textural images, the matching result is affected by low contrast, repetitive patterns, discontinuity or occlusion, few or homogeneous textures. Recently, graph matching became popular for its integration of geometric and radiometric information. Focused on poor textural image matching problem, it is proposed an edge-weight strategy to improve graph matching algorithm. A series of experiments have been conducted including 4 typical landscapes: Forest, desert, farmland, and urban areas. And it is experimentally found that our new algorithm achieves better performance. Compared to SIFT, doubled corresponding points were acquired, and the overall recall rate reached up to 68%, which verifies the feasibility and effectiveness of the algorithm.
A study on the automation of scanner matching
NASA Astrophysics Data System (ADS)
He, Yuan; Serebryakov, Alexander; Light, Scott; Jain, Vivek; Byers, Erik; Goossens, Ronald; Niu, Zhi-Yuan; Engblom, Peter; Larson, Scott; Geh, Bernd; Hickman, Craig; Kang, Hoyoung
2013-04-01
Scanner matching based on CD or patterning contours has been demonstrated in past works. All of these published works require extensive wafer metrology. In contrast, this work extends a previously proposed optical pattern matching method that requires little metrology by adding the component requirements and the procedure for creating an automation flow. In a test case, we matched an ASML XT:1900i using a DOE to an ASML NXT:1950i scanner using FlexRay. The matching was conducted on a 4x nm process test layer as a development vehicle for the 2x nm product nodes. The paper summarizes the before and after matching data and analysis, with future opportunities for improvements suggested.
A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle
Gao, Xiaotian; Jiang, Binhao
2015-06-21
In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods.
Stereo matching using Hebbian learning.
Pajares, G; Cruz, J M; Lopez-Orozco, J A
1999-01-01
This paper presents an approach to the local stereo matching problem using edge segments as features with several attributes. We have verified that the differences in attributes for the true matches cluster in a cloud around a center. The correspondence is established on the basis of the minimum distance criterion, computing the Mahalanobis distance between the difference of the attributes for a current pair of features and the cluster center (similarity constraint). We introduce a learning strategy based on the Hebbian Learning to get the best cluster center. A comparative analysis among methods without learning and with other learning strategies is illustrated. PMID:18252332
Memristor-based pattern matching
NASA Astrophysics Data System (ADS)
Klimo, Martin; Such, Ondrej; Skvarek, Ondrej; Fratrik, Milan
2014-10-01
Pattern matching is a machine learning area that requires high-performance hardware. It has been hypothesized that massively parallel designs, which avoid von Neumann architecture, could provide a significant performance boost. Such designs can advantageously use memristive switches. This paper discusses a two-stage design that implements the induced ordered weighted average (IOWA) method for pattern matching. We outline the circuit structure and discuss how a functioning circuit can be achieved using metal oxide devices. We describe our simulations of memristive circuits and illustrate their performance on a vowel classification task.
2014-01-01
There have been significant problems in ultrasound training since the introduction of the new postgraduate curriculum for obstetrics and gynaecology. It is therefore important to understand how the skill of ultrasound is acquired in order to be able to improve the training program. Here, the potential application of the Dreyfus model of skill acquisition has been analysed to map the progression from novice to master and the progressions between each stage analysed. Although the Dreyfus model is not a perfect match for ultrasound scanning, it provides us with a theoretical framework on which to underpin educational practice in this field.
Morganti, Kristy Gonzalez; Lovejoy, Susan; Beckjord, Ellen Burke; Haviland, Amelia M; Haas, Ann C; Farley, Donna O
2014-01-01
This study evaluated how the Perfecting Patient Care (PPC) University, a quality improvement (QI) training program for health care leaders and clinicians, affected the ability of organizations to improve the health care they provide. This training program teaches improvement methods based on Lean concepts and principles of the Toyota Production System and is offered in several formats. A retrospective evaluation was performed that gathered data on training, other process factors, and outcomes after staff completed the PPC training. A majority of respondents reported gaining QI competencies and cultural achievements from the training. Organizations had high average scores for the success measures of "outcomes improved" and "sustainable monitoring" but lower scores for diffusion of QI efforts. Total training dosage was significantly associated with the measures of QI success. This evaluation provides evidence that organizations gained the PPC competencies and cultural achievements and that training dosage is a driver of QI success. PMID:23572230
Latent Fingerprint Matching: Performance Gain via Feedback from Exemplar Prints.
Arora, Sunpreet S; Liu, Eryun; Cao, Kai; Jain, Anil K
2014-12-01
Latent fingerprints serve as an important source of forensic evidence in a court of law. Automatic matching of latent fingerprints to rolled/plain (exemplar) fingerprints with high accuracy is quite vital for such applications. However, latent impressions are typically of poor quality with complex background noise which makes feature extraction and matching of latents a significantly challenging problem. We propose incorporating top-down information or feedback from an exemplar to refine the features extracted from a latent for improving latent matching accuracy. The refined latent features (e.g. ridge orientation and frequency), after feedback, are used to re-match the latent to the top K candidate exemplars returned by the baseline matcher and resort the candidate list. The contributions of this research include: (i) devising systemic ways to use information in exemplars for latent feature refinement, (ii) developing a feedback paradigm which can be wrapped around any latent matcher for improving its matching performance, and (iii) determining when feedback is actually necessary to improve latent matching accuracy. Experimental results show that integrating the proposed feedback paradigm with a state-of-the-art latent matcher improves its identification accuracy by 0.5-3.5 percent for NIST SD27 and WVU latent databases against a background database of 100k exemplars. PMID:26353151
7 CFR 2903.5 - Matching requirements.
Code of Federal Regulations, 2010 CFR
2010-01-01
..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...
7 CFR 2903.5 - Matching requirements.
Code of Federal Regulations, 2011 CFR
2011-01-01
..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...
7 CFR 2903.5 - Matching requirements.
Code of Federal Regulations, 2014 CFR
2014-01-01
..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...
7 CFR 2903.5 - Matching requirements.
Code of Federal Regulations, 2012 CFR
2012-01-01
..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...
7 CFR 2903.5 - Matching requirements.
Code of Federal Regulations, 2013 CFR
2013-01-01
..., DEPARTMENT OF AGRICULTURE BIODIESEL FUEL EDUCATION PROGRAM General Information § 2903.5 Matching requirements. There are no matching funds requirements for the Biodiesel Fuel Education Program and matching...
Project MATCH: Training for a Promotora Intervention
Swider, Susan M.; Martin, Molly; Lynas, Carmen; Rothschild, Steven
2013-01-01
Purpose Adequate training and support are critical for community health workers (promotoras de salud in Spanish) to work effectively. Current literature on promotora training is limited by a focus on promotoras' knowledge and satisfaction immediately after training. The relevance of training to subsequent work performance and the need for ongoing training are rarely addressed. This paper describes the training and evaluation components of a promotora intervention focused on diabetes self management. Training Methods Project MATCH (the Mexican American Trial of Community Health Workers) is a clinical trial designed to test the effectiveness of an intensive, promotora-based intervention to improve disease self-management for Mexican-Americans with diabetes. The MATCH investigators designed a multi-component promotora training program that provided both initial and ongoing training. The investigators used multiple methods to determine promotoras' knowledge levels, initial competency in intervention delivery, and changes in this competency over time. Evaluation Methods and Results The evaluation results show that while the initial training provided a solid knowledge and skills base for the promotoras, the ongoing training was critical in helping them deal with both intervention-related and personal challenges. Conclusions The experiences of the MATCH study suggest that in addition to strong initial training, promotora interventions benefit from ongoing training and evaluation to ensure success. PMID:20008279
Stereo matching using epipolar distance transform.
Yang, Qingxiong; Ahuja, Narendra
2012-10-01
In this paper, we propose a simple but effective image transform, called the epipolar distance transform, for matching low-texture regions. It converts image intensity values to a relative location inside a planar segment along the epipolar line, such that pixels in the low-texture regions become distinguishable. We theoretically prove that the transform is affine invariant, thus the transformed images can be directly used for stereo matching. Any existing stereo algorithms can be directly used with the transformed images to improve reconstruction accuracy for low-texture regions. Results on real indoor and outdoor images demonstrate the effectiveness of the proposed transform for matching low-texture regions, keypoint detection, and description for low-texture scenes. Our experimental results on Middlebury images also demonstrate the robustness of our transform for highly textured scenes. The proposed transform has a great advantage, its low computational complexity. It was tested on a MacBook Air laptop computer with a 1.8 GHz Core i7 processor, with a speed of about 9 frames per second for a video graphics array-sized image. PMID:22801509
Impact of a soccer match on the cardiac autonomic control of referees.
Boullosa, Daniel Alexandre; Abreu, Laurinda; Tuimil, José Luis; Leicht, Anthony Scott
2012-06-01
The purpose of this study was to assess the effect of a soccer match on the cardiac autonomic control of heart rate (HR) in soccer referees. Sixteen Spanish regional and third division referees (11 males: 26 ± 7 years, 74.4 ± 4.1 kg, 178 ± 3 cm, Yo-Yo IR1 ~600-1,560 m; 5 females: 22 ± 3 years, 59.3 ± 4.8 kg, 158 ± 8 cm, Yo-Yo IR1 ~200-520 m) participated with 24-h HR recordings measured with a Polar RS800 during a rest and a match day. Autonomic control of HR was assessed from HR variability (HRV) analysis. Inclusion of a soccer match (92.5% spent at >75% maximum HR) reduced pre-match (12:00-17:00 hours; small to moderate), post-match (19:00-00:00 hours; moderate to almost perfect), and night-time (00:00-05:00 hours; small to moderate) HRV. Various moderate-to-large correlations were detected between resting HRV and the rest-to-match day difference in HRV. The rest-to-match day differences of low and high-frequency bands ratio (LF/HF) and HR in the post-match period were moderately correlated with time spent at different exercise intensities. Yo-Yo IR1 performance was highly correlated with jump capacity and peak lactate, but not with any HRV parameter. These results suggest that a greater resting HRV may allow referees to tolerate stresses during a match day with referees who spent more time at higher intensities during matches exhibiting a greater LF/HF increment in the post-match period. The relationship between match activities, [Formula: see text] and HR recovery kinetics in referees and team sport athletes of different competitive levels remains to be clarified. PMID:21997680
A stereo matching handling model in low-texture region
NASA Astrophysics Data System (ADS)
Ma, Yi; Zhang, Yi; Han, Jin; Bai, Lianfa
2015-10-01
In binocular stereo matching, mistakes are relatively easy to appear in low-texture region due to the weak detail information. In order to eliminate the matching ambiguity as well as guarantee the matching rate, this paper proposes a stereo matching algorithm based on image segmentation. In most low-texture region, traditional cost functions are usually used, and the algorithm can only ameliorated through methods such as reasonable support window, dynamic programming and so on. The results of these algorithms make the whole image smooth, and lose many details. The matching cost function in our algorithm is based on the assumption that pixels are similar in homogeneous area, and reduce the use of multiplication so as to obtain better visual effects and decrease the computational complexity. The first is forming the segmentation maps of stereoscopic images as the guidance. Next comes calculating the aggregation cost in stereo matching in both horizontal and vertical direction successively referring to the segmentation maps. Eventually achieving the final disparity map with optimization algorithm, using WTA(Winner-Takes-All) as principle. The computational complexity of this algorithm is independent of the window size, and suitable for different sizes and shapes. The results of experimental show that this algorithm can get better matching precision about the colorful low-texture stereo image pairs, with few increase in computational complexity. This algorithm, to some extent, can improve the match quality of the regions with repeat texture.
Automatic Background Knowledge Selection for Matching Biomedical Ontologies
Faria, Daniel; Pesquita, Catia; Santos, Emanuel; Cruz, Isabel F.; Couto, Francisco M.
2014-01-01
Ontology matching is a growing field of research that is of critical importance for the semantic web initiative. The use of background knowledge for ontology matching is often a key factor for success, particularly in complex and lexically rich domains such as the life sciences. However, in most ontology matching systems, the background knowledge sources are either predefined by the system or have to be provided by the user. In this paper, we present a novel methodology for automatically selecting background knowledge sources for any given ontologies to match. This methodology measures the usefulness of each background knowledge source by assessing the fraction of classes mapped through it over those mapped directly, which we call the mapping gain. We implemented this methodology in the AgreementMakerLight ontology matching framework, and evaluate it using the benchmark biomedical ontology matching tasks from the Ontology Alignment Evaluation Initiative (OAEI) 2013. In each matching problem, our methodology consistently identified the sources of background knowledge that led to the highest improvements over the baseline alignment (i.e., without background knowledge). Furthermore, our proposed mapping gain parameter is strongly correlated with the F-measure of the produced alignments, thus making it a good estimator for ontology matching techniques based on background knowledge. PMID:25379899
Automatic background knowledge selection for matching biomedical ontologies.
Faria, Daniel; Pesquita, Catia; Santos, Emanuel; Cruz, Isabel F; Couto, Francisco M
2014-01-01
Ontology matching is a growing field of research that is of critical importance for the semantic web initiative. The use of background knowledge for ontology matching is often a key factor for success, particularly in complex and lexically rich domains such as the life sciences. However, in most ontology matching systems, the background knowledge sources are either predefined by the system or have to be provided by the user. In this paper, we present a novel methodology for automatically selecting background knowledge sources for any given ontologies to match. This methodology measures the usefulness of each background knowledge source by assessing the fraction of classes mapped through it over those mapped directly, which we call the mapping gain. We implemented this methodology in the AgreementMakerLight ontology matching framework, and evaluate it using the benchmark biomedical ontology matching tasks from the Ontology Alignment Evaluation Initiative (OAEI) 2013. In each matching problem, our methodology consistently identified the sources of background knowledge that led to the highest improvements over the baseline alignment (i.e., without background knowledge). Furthermore, our proposed mapping gain parameter is strongly correlated with the F-measure of the produced alignments, thus making it a good estimator for ontology matching techniques based on background knowledge. PMID:25379899
The Vector Matching Method in Geomagnetic Aiding Navigation
Song, Zhongguo; Zhang, Jinsheng; Zhu, Wenqi; Xi, Xiaoli
2016-01-01
In this paper, a geomagnetic matching navigation method that utilizes the geomagnetic vector is developed, which can greatly improve the matching probability and positioning precision, even when the geomagnetic entropy information in the matching region is small or the geomagnetic contour line’s variety is obscure. The vector iterative closest contour point (VICCP) algorithm that is proposed here has better adaptability with the positioning error characteristics of the inertial navigation system (INS), where the rigid transformation in ordinary ICCP is replaced with affine transformation. In a subsequent step, a geomagnetic vector information fusion algorithm based on Bayesian statistical analysis is introduced into VICCP to improve matching performance further. Simulations based on the actual geomagnetic reference map have been performed for the validation of the proposed algorithm. PMID:27447645
The Vector Matching Method in Geomagnetic Aiding Navigation.
Song, Zhongguo; Zhang, Jinsheng; Zhu, Wenqi; Xi, Xiaoli
2016-01-01
In this paper, a geomagnetic matching navigation method that utilizes the geomagnetic vector is developed, which can greatly improve the matching probability and positioning precision, even when the geomagnetic entropy information in the matching region is small or the geomagnetic contour line's variety is obscure. The vector iterative closest contour point (VICCP) algorithm that is proposed here has better adaptability with the positioning error characteristics of the inertial navigation system (INS), where the rigid transformation in ordinary ICCP is replaced with affine transformation. In a subsequent step, a geomagnetic vector information fusion algorithm based on Bayesian statistical analysis is introduced into VICCP to improve matching performance further. Simulations based on the actual geomagnetic reference map have been performed for the validation of the proposed algorithm. PMID:27447645
Matching Teacher and Learner Styles.
ERIC Educational Resources Information Center
Howell, John F.; Erickson, Marilyn R.
This study focuses on the question of "emotional style," defined as the structure or lack of structure in the interaction between teacher and student. Characteristics of "open" and "structured" teachers and students are defined. It is hypothesized that a matching of teacher and student emotional style will result in greater student achievement. A…
Acceptable Ungrammaticality in Sentence Matching
ERIC Educational Resources Information Center
Duffield, Nigel; Matsuo, Ayumi; Roberts, Leah
2007-01-01
This article presents a new set of experiments using the "sentence-matching paradigm" (Forster, 1979; Freedman and Forster, 1985; see also Bley-Vroman and Masterson, 1989), investigating native speakers' and second language (L2) learners' knowledge of constraints on clitic placement in French. Our purpose is three-fold: (1) to shed more light on…
Federal Register 2010, 2011, 2012, 2013, 2014
2013-12-05
... HUMAN SERVICES Centers for Medicare & Medicaid Services Privacy Act of 1974: CMS Computer Matching Program Match No. 2013-01; HHS Computer Matching Program Match No. 1312 AGENCY: Centers for Medicare & Medicaid Services (CMS), Department of Health and Human Services (HHS). ACTION: Notice of Computer...
Applying Matched Sampling to Evaluate a University Tutoring Program for First-Year Students
ERIC Educational Resources Information Center
Walvoord, Mark E.; Pleitz, Jacob D.
2016-01-01
Our study used a case-control matching design to assess the influence of a voluntary tutoring program in improving first-year students' Grade Point Averages (GPA). To evaluate program effectiveness, we applied case-control matching to obtain 215 pairs of students with or without participation in tutoring, but matched on high school GPA and…
Binary adaptive semi-global matching based on image edges
NASA Astrophysics Data System (ADS)
Hu, Han; Rzhanov, Yuri; Hatcher, Philip J.; Bergeron, R. D.
2015-07-01
Image-based modeling and rendering is currently one of the most challenging topics in Computer Vision and Photogrammetry. The key issue here is building a set of dense correspondence points between two images, namely dense matching or stereo matching. Among all dense matching algorithms, Semi-Global Matching (SGM) is arguably one of the most promising algorithms for real-time stereo vision. Compared with global matching algorithms, SGM aggregates matching cost from several (eight or sixteen) directions rather than only the epipolar line using Dynamic Programming (DP). Thus, SGM eliminates the classical "streaking problem" and greatly improves its accuracy and efficiency. In this paper, we aim at further improvement of SGM accuracy without increasing the computational cost. We propose setting the penalty parameters adaptively according to image edges extracted by edge detectors. We have carried out experiments on the standard Middlebury stereo dataset and evaluated the performance of our modified method with the ground truth. The results have shown a noticeable accuracy improvement compared with the results using fixed penalty parameters while the runtime computational cost was not increased.
Theory of patch-antenna metamaterial perfect absorbers
NASA Astrophysics Data System (ADS)
Bowen, Patrick T.; Baron, Alexandre; Smith, David R.
2016-06-01
A metasurface that absorbs waves from all directions of incidence can be achieved if the surface impedance is made to vary as a function of incidence angle in a specific manner. Here we show that a periodic array of planar nanoparticles coupled to a metal film can act as an absorbing metasurface with an angle-dependent impedance. Through a semi-analytical calculation based on coupled-mode theory, we find the perfect absorbing condition is equivalent to balancing the Ohmic and radiative losses of the nanoparticles at normal incidence. Absorption over a wide range of incidence angles can then be obtained by tailoring the scattered far-field pattern of the individual planar nanoparticles such that their radiative losses remain constant. The theory provides a means of understanding the behavior of perfect absorbing structures that have been observed experimentally or numerically, reconciling previously published theories and enabling the optimization of absorbing surfaces.
Perfectly absorbing ultra thin interference coatings for hydrogen sensing.
Serhatlioglu, Murat; Ayas, Sencer; Biyikli, Necmi; Dana, Aykutlu; Solmaz, Mehmet E
2016-04-15
Here we numerically demonstrate a straightforward method for optical detection of hydrogen gas by means of absorption reduction and colorimetric indication. A perfectly absorbing metal-insulator-metal (MIM) thin film interference structure is constructed using a silver metal back reflector, silicon dioxide insulator, and palladium as the upper metal layer and hydrogen catalyst. The thickness of silicon dioxide allows the maximizing of the electric field intensity at the Air/SiO_{2} interface at the quarter wavelengths and enabling perfect absorption with the help of highly absorptive palladium thin film (∼7 nm). While the exposure of the MIM structure to H_{2} moderately increases reflection, the relative intensity contrast due to formation of metal hydride is extensive. By modifying the insulator film thickness and hence the spectral absorption, the color is tuned and eye-visible results are obtained. PMID:27082329
Perfect function transfer and interference effects in interacting boson lattices
Wu Lianao; Miranowicz, Adam; Wang Xiangbin; Liu Yuxi; Nori, Franco
2009-07-15
We show how to perfectly transfer, without state initialization and remote collaboration, arbitrary functions in interacting boson lattices. We describe a possible implementation of state transfer through bosonic atoms trapped in optical lattices or polaritons in on-chip coupled cavities. Significantly, a family of Hamiltonians, both linear and nonlinear, is found which are related to the Bose-Hubbard model and that enable the perfect transfer of arbitrary functions. It is shown that the state transfer between two sites in two-dimensional lattices can result in quantum interference due to the different numbers of intermediate sites in different paths. The signature factor in nuclear physics can be useful to characterize this quantum interference.
Recovery of data from perfectly twinned virus crystals revisited
Ginn, Helen Mary; Stuart, David Ian
2016-01-01
Perfect merohedral twinning of crystals is not uncommon and complicates structural analysis. An iterative method for the deconvolution of data from perfectly merohedrally twinned crystals in the presence of noncrystallographic symmetry (NCS) has been reimplemented. It is shown that the method recovers the data effectively using test data, and an independent metric of success, based on special classes of reflections that are unaffected by the twin operator, is now provided. The method was applied to a real problem with fivefold NCS and rather poor-quality diffraction data, and it was found that even in these circumstances the method appears to recover most of the information. The software has been made available in a form that can be applied to other crystal systems. PMID:27303802
Perfect fluids in the Einstein-Cartan theory
NASA Technical Reports Server (NTRS)
Ray, J. R.; Smalley, L. J.
1982-01-01
It is pointed out that whereas most of the discussion of the Einstein-Cartan (EC) theory involves the relationship between gravitation and elementary particles, it is possible that the theory, if correct, may be important in certain extreme astrophysical and cosmological problems. The latter would include something like the collapse of a spinning star or an early universe with spin. A set of equations that describe a macroscopic perfect fluid in the EC theory is derived and examined. The equations are derived starting from the fundamental variational principle for a perfect fluid in general relativity. A brief review of the study by Ray (1972) is included, and the results for the EC theory are presented.
Nonlocal memory effects allow perfect teleportation with mixed states
Laine, Elsi-Mari; Breuer, Heinz-Peter; Piilo, Jyrki
2014-01-01
One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of nonlocal memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks. PMID:24714695
Holographic perfect shuffle permutation element for a miniaturized switching network
NASA Astrophysics Data System (ADS)
Kobolla, H.; Schmidt, J.; Gluch, E.; Schwider, J.
1995-06-01
A holographic perfect shuffle element with 80 channels for a miniaturized switching network is reported. An array of vertical-cavity, surface-emitting lasers is used as a transmitter. The whole permutation is carried out totally in glass. The 80 channels are permuted within a rectangle with a volume of 3 mm \\times 4 mm \\times 2 mm. Four planes of stacked volume holograms recorded in dichromated gelatin form this perfect shuffle element with an angular spectrum between 7 deg and 35 deg. Changes in the wavelength of the diode lasers to Delta lambda = +/-10 nm can be compensated with this setup. The overall efficiency per channel lies between 40% and 60%. When Fresnel reflections and absorption are taken into account, a transmission per hologram between 78% and 90% is achieved.
Thermodynamics of perfect fluids from scalar field theory
NASA Astrophysics Data System (ADS)
Ballesteros, Guillermo; Comelli, Denis; Pilo, Luigi
2016-07-01
The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields. These scalars describe the embedding in spacetime of the medium and play the role of Stückelberg fields for spontaneously broken spatial and time translations. Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar. We explore the relation between the field theory description of perfect fluids to thermodynamics. By drawing the correspondence between the allowed operators at leading order in derivatives and the thermodynamic variables, we find that a complete thermodynamic picture requires the four Stückelberg fields. We show that thermodynamic stability plus the null-energy condition imply dynamical stability. We also argue that a consistent thermodynamic interpretation is not possible if any of the shift symmetries is explicitly broken.
Thickening the string. I. The string perfect dust
NASA Astrophysics Data System (ADS)
Stachel, John
1980-04-01
The classical theory of the geometrical string is developed as the theory of a simple, surface-forming timelike bivector field in an arbitrary background space-time. The stress-energy tensor for a perfect dust of such strings is written down, and the conservation laws for such a dust, as well as the equations of motion of the string, are derived from the vanishing of the divergence of the stress-energy tensor. (The boundary conditions for the open string are also derived from the junction conditions for the stress-energy tensor in Appendix A.) The generalization of this model to null strings, and to a perfect fluid of strings, are discussed, and will form the subject of the second and third papers in this series. The problem of a fully general-relativistic string theory, and an alternate approach to the string, based upon defining an acceleration tensor for two- (and higher) dimensional subspaces, are also discussed.
Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering.
Wang, M; Gong, Q H; Ficek, Z; He, Q Y
2015-01-01
A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror. PMID:26212901
Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering
NASA Astrophysics Data System (ADS)
Wang, M.; Gong, Q. H.; Ficek, Z.; He, Q. Y.
2015-07-01
A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror.
Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers
Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo
2015-01-26
Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.
Nonlocal memory effects allow perfect teleportation with mixed states.
Laine, Elsi-Mari; Breuer, Heinz-Peter; Piilo, Jyrki
2014-01-01
One of the most striking consequences of quantum physics is quantum teleportation - the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of nonlocal memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks. PMID:24714695
Recovery of data from perfectly twinned virus crystals revisited.
Ginn, Helen Mary; Stuart, David Ian
2016-06-01
Perfect merohedral twinning of crystals is not uncommon and complicates structural analysis. An iterative method for the deconvolution of data from perfectly merohedrally twinned crystals in the presence of noncrystallographic symmetry (NCS) has been reimplemented. It is shown that the method recovers the data effectively using test data, and an independent metric of success, based on special classes of reflections that are unaffected by the twin operator, is now provided. The method was applied to a real problem with fivefold NCS and rather poor-quality diffraction data, and it was found that even in these circumstances the method appears to recover most of the information. The software has been made available in a form that can be applied to other crystal systems. PMID:27303802
Perfect gas effects in compressible rapid distortion theory
NASA Technical Reports Server (NTRS)
Kerschen, E. J.; Myers, M. R.
1987-01-01
The governing equations presented for small amplitude unsteady disturbances imposed on steady, compressible mean flows that are two-dimensional and nearly uniform have their basis in the perfect gas equations of state, and therefore generalize previous results based on tangent gas theory. While these equations are more complex, this complexity is required for adequate treatment of high frequency disturbances, especially when the base flow Mach number is large; under such circumstances, the simplifying assumptions of tangent gas theory are not applicable.
Comment on ''Perfect imaging with positive refraction in three dimensions''
Merlin, R.
2010-11-15
Leonhardt and Philbin [Phys. Rev. A 81, 011804(R) (2010)] have recently constructed a mathematical proof that the Maxwell's fish-eye lens provides perfect imaging of electromagnetic waves without negative refraction. In this comment, we argue that the unlimited resolution is an artifact of having introduced an unphysical drain at the position of the geometrical image. The correct solution gives focusing consistent with the standard diffraction limit.
Perfect teleportation and superdense coding with W states
Agrawal, Pankaj; Pati, Arun
2006-12-15
True tripartite entanglement of the state of a system of three qubits can be classified on the basis of stochastic local operations and classical communications. Such states can be classified into two categories: GHZ states and W states. It is known that GHZ states can be used for teleportation and superdense coding, but the prototype W state cannot be. However, we show that there is a class of W states that can be used for perfect teleportation and superdense coding.
Characterization of quantum circulant networks having perfect state transfer
NASA Astrophysics Data System (ADS)
Bašić, Milan
2013-01-01
In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph G, which is characterized by its circulant adjacency matrix A. Formally, we say that there exists a perfect state transfer (PST) between vertices {a,bin V(G)} if | F( τ) ab | = 1, for some positive real number τ, where F( t) = exp(i At). Saxena et al. (Int J Quantum Inf 5:417-430, 2007) proved that | F( τ) aa | = 1 for some {ain V(G)} and {tauin {R}^+} if and only if all eigenvalues of G are integer (that is, the graph is integral). The integral circulant graph ICG n ( D) has the vertex set Z n = {0, 1, 2, . . . , n - 1} and vertices a and b are adjacent if {gcd(a-b,n)in D} , where {D subseteq {d : d mid n, 1 ≤ d < n}} . These graphs are highly symmetric and have important applications in chemical graph theory. We show that ICG n ( D) has PST if and only if {nin 4{N}} and {D=widetilde{D_3} \\cup D_2\\cup 2D_2\\cup 4D_2|cup {n/2^a}} , where {widetilde{D_3}={din D | n/din 8{N}}, D_2= {din D | n/din 8{N}+4}{setminus}{n/4}} and {ain{1,2}} . We have thus answered the question of complete characterization of perfect state transfer in integral circulant graphs raised in Angeles-Canul et al. (Quantum Inf Comput 10(3&4):0325-0342, 2010). Furthermore, we also calculate perfect quantum communication distance (distance between vertices where PST occurs) and describe the spectra of integral circulant graphs having PST. We conclude by giving a closed form expression calculating the number of integral circulant graphs of a given order having PST.
Covariant diagonalization of the perfect fluid stress-energy tensor
NASA Astrophysics Data System (ADS)
Garat, Alcides
2015-02-01
We introduce new tetrads that manifestly and covariantly diagonalize the stress-energy tensor for a perfect fluid with vorticity at every spacetime point. This new tetrad can be applied to introduce simplification in the analysis of astrophysical relativistic problems where vorticity is present through the Carter-Lichnerowicz equation. We also discuss the origin of inertia in this special case from the standpoint of our new local tetrads.
Hamiltonian formalism for perfect fluids in general relativity
Demaret, J.; Moncrief, V.
1980-05-15
Schutz's Hamiltonian theory of a relativistic perfect fluid, based on the velocity-potential version of classical perfect fluid hydrodynamics as formulated by Seliger and Whitham, is used to derive, in the framework of the Arnowitt, Deser, and Misner (ADM) method, a general partially reduced Hamiltonian for relativistic systems filled with a perfect fluid. The time coordinate is chosen, as in Lund's treatment of collapsing balls of dust, as minus the only velocity potential different from zero in the case of an irrotational and isentropic fluid. A ''semi-Dirac'' method can be applied to quantize astrophysical and cosmological models in the framework of this partially reduced formalism. If one chooses Taub's adapted comoving coordinate system, it is possible to derive a fully reduced ADM Hamiltonian, which is equal to minus the total baryon number of the fluid, generalizing a result previously obtained by Moncrief in the more particular framework of Taub's variational principle, valid for self-gravitating barotropic relativistic perfect fluids. An unconstrained Hamiltonian density is then explicitly derived for a fluid obeying the equation of state p=(gamma-1)rho (1 < or = ..gamma.. < or = 2), which can adequately describe the phases of very high density attained in a catastrophic collapse or during the early stages of the Universe. This Hamiltonian density, shown to be equivalent to Moncrief's in the particular case of an isentropic fluid, can be simplified for fluid-filled class-A diagonal Bianchi-type cosmological models and appears as a suitable starting point for the study of the canonical quantization of these models.
Gold-Mediated Exfoliation of Ultralarge Optoelectronically-Perfect Monolayers.
Desai, Sujay B; Madhvapathy, Surabhi R; Amani, Matin; Kiriya, Daisuke; Hettick, Mark; Tosun, Mahmut; Zhou, Yuzhi; Dubey, Madan; Ager, Joel W; Chrzan, Daryl; Javey, Ali
2016-06-01
Gold-mediated exfoliation of ultralarge optoelectronically perfect monolayers with lateral dimensions up to ≈500 μm is reported. Electrical, optical, and X-ray photo-electron spectroscopy characterization show that the quality of the gold-exfoliated flakes is similar to that of tape-exfoliated flakes. Large-area flakes allow manufacturing of large-area mono-layer transition metal dichalcogenide electronics. PMID:27007751
Geodesic Components Of Integrated Optics: Seeking For The Perfect Lens
NASA Astrophysics Data System (ADS)
Sochacki, Jacek
1986-11-01
The most recent formulation of the geodesic lens problem is briefly discussed and proved very useful in developing novel solutions. A new family of perfectly imaging lenses is presented, which lends itself extremely well to the integrated-optical circuits. These lenses possess smooth transition between the cyllindrically-symmetric depression profile and the flat guide. Moreover, the rounded section profile is characterized by non-vanishing local curvature radius. This should minimize radiation and scattering losses by the guided modes.
ERIC Educational Resources Information Center
Monahan, Patrick O.; Ankenmann, Robert D.
2010-01-01
When the matching score is either less than perfectly reliable or not a sufficient statistic for determining latent proficiency in data conforming to item response theory (IRT) models, Type I error (TIE) inflation may occur for the Mantel-Haenszel (MH) procedure or any differential item functioning (DIF) procedure that matches on summed-item…
Template matching on parallel architectures
Sher
1985-07-01
Many important problems in computer vision can be characterized as template-matching problems on edge images. Some examples are circle detection and line detection. Two techniques for template matching are the Hough transform and correlation. There are two algorithms for correlation: a shift-and-add-based technique and a Fourier-transform-based technique. The most efficient algorithm of these three varies depending on the size of the template and the structure of the image. On different parallel architectures, the choice of algorithms for a specific problem is different. This paper describes two parallel architectures: the WARP and the Butterfly and describes why and how the criterion for making the choice of algorithms differs between the two machines.
University Reactor Matching Grants Program
John Valentine; Farzad Rahnema; Said Abdel-Khalik
2003-02-14
During the 2002 Fiscal year, funds from the DOE matching grant program, along with matching funds from the industrial sponsors, have been used to support research in the area of thermal-hydraulics. Both experimental and numerical research projects have been performed. Experimental research focused on two areas: (1) Identification of the root cause mechanism for axial offset anomaly in pressurized water reactors under prototypical reactor conditions, and (2) Fluid dynamic aspects of thin liquid film protection schemes for inertial fusion reactor chambers. Numerical research focused on two areas: (1) Multi-fluid modeling of both two-phase and two-component flows for steam conditioning and mist cooling applications, and (2) Modeling of bounded Rayleigh-Taylor instability with interfacial mass transfer and fluid injection through a porous wall simulating the ''wetted wall'' protection scheme in inertial fusion reactor chambers. Details of activities in these areas are given.
Photometric invariant stereo matching method.
Gu, Feifei; Zhao, Hong; Zhou, Xiang; Li, Jinjun; Bu, Penghui; Zhao, Zixin
2015-12-14
A robust stereo matching method based on a comprehensive mathematical model for color formation process is proposed to estimate the disparity map of stereo images with noise and photometric variations. The band-pass filter with DoP kernel is firstly used to filter out noise component of the stereo images. Then the log-chromaticity normalization process is applied to eliminate the influence of lightning geometry. All the other factors that may influence the color formation process are removed through the disparity estimation process with a specific matching cost. Performance of the developed method is evaluated by comparing with some up-to-date algorithms. Experimental results are presented to demonstrate the robustness and accuracy of the method. PMID:26698970
Observational Studies: Matching or Regression?
Brazauskas, Ruta; Logan, Brent R
2016-03-01
In observational studies with an aim of assessing treatment effect or comparing groups of patients, several approaches could be used. Often, baseline characteristics of patients may be imbalanced between groups, and adjustments are needed to account for this. It can be accomplished either via appropriate regression modeling or, alternatively, by conducting a matched pairs study. The latter is often chosen because it makes groups appear to be comparable. In this article we considered these 2 options in terms of their ability to detect a treatment effect in time-to-event studies. Our investigation shows that a Cox regression model applied to the entire cohort is often a more powerful tool in detecting treatment effect as compared with a matched study. Real data from a hematopoietic cell transplantation study is used as an example. PMID:26712591
32 CFR 806b.50 - Computer matching.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 32 National Defense 6 2012-07-01 2012-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...
32 CFR 806b.50 - Computer matching.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 32 National Defense 6 2010-07-01 2010-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...
32 CFR 806b.50 - Computer matching.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 32 National Defense 6 2014-07-01 2014-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...
32 CFR 806b.50 - Computer matching.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 32 National Defense 6 2011-07-01 2011-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...
32 CFR 806b.50 - Computer matching.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 32 National Defense 6 2013-07-01 2013-07-01 false Computer matching. 806b.50 Section 806b.50... PROGRAM Disclosing Records to Third Parties § 806b.50 Computer matching. Computer matching programs... on forms used in applying for benefits. Coordinate computer matching statements on forms with...
Practical multi-featured perfect absorber utilizing high conductivity silicon
NASA Astrophysics Data System (ADS)
Gok, Abdullah; Yilmaz, Mehmet; Bıyıklı, Necmi; Topallı, Kağan; Okyay, Ali K.
2016-03-01
We designed all-silicon, multi-featured band-selective perfect absorbing surfaces based on CMOS compatible processes. The center wavelength of the band-selective absorber can be varied between 2 and 22 μm while a bandwidth as high as 2.5 μm is demonstrated. We used a silicon-on-insulator (SOI) wafer which consists of n-type silicon (Si) device layer, silicon dioxide (SiO2) as buried oxide layer, and n-type Si handle layer. The center wavelength and bandwidth can be tuned by adjusting the conductivity of the Si device and handle layers as well as the thicknesses of the device and buried oxide layers. We demonstrate proof-of-concept absorber surfaces experimentally. Such absorber surfaces are easy to microfabricate because the absorbers do not require elaborate microfabrication steps such as patterning. Due to the structural simplicity, low-cost fabrication, wide spectrum range of operation, and band properties of the perfect absorber, the proposed multi-featured perfect absorber surfaces are promising for many applications. These include sensing devices, surface enhanced infrared absorption applications, solar cells, meta-materials, frequency selective sensors and modulators.
Thin Perfect Absorbers for Electromagnetic Waves: Theory, Design, and Realizations
NASA Astrophysics Data System (ADS)
Ra'di, Y.; Simovski, C. R.; Tretyakov, S. A.
2015-03-01
With recent advances in nanophotonics and nanofabrication, considerable progress has been achieved in realizations of thin composite layers designed for full absorption of incident electromagnetic radiation, from microwaves to the visible. If the layer is structured at a subwavelength scale, thin perfect absorbers are usually called "metamaterial absorbers," because these composite structures are designed to emulate some material responses not reachable with any natural material. On the other hand, many thin absorbing composite layers were designed and used already in the time of the introduction of radar technology, predominantly as a means to reduce radar visibility of targets. In view of a wide variety of classical and new topologies of optically thin metamaterial absorbers and plurality of applications, there is a need for a general, conceptual overview of the fundamental mechanisms of full absorption of light or microwave radiation in thin layers. Here, we present such an overview in the form of a general theory of thin perfectly absorbing layers. Possible topologies of perfect metamaterial absorbers are classified based on their fundamental operational principles. For each of the identified classes, we provide design equations and give examples of particular realizations. The concluding section provides a summary and gives an outlook on future developments in this field.
High-speed cylindrical collapse of two perfect fluids
NASA Astrophysics Data System (ADS)
Sharif, M.; Ahmad, Zahid
2007-09-01
In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by c s , d s . It is shown that the high-speed approximation scheme breaks down by non-zero pressures p 1, p 2 when c s , d s are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainty on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa (Prog Theor Phys 113:73, 2005) for the perfect fluid.
Near-perfect bilayer growth of Pb on Ge(111)
NASA Astrophysics Data System (ADS)
Murat Özer, M.; Weitering, Hanno H.
2004-03-01
Understanding electrical transport through nanostructures requires almost perfect control of their structure and morphology, which can sometimes be achieved via self assembly. Quantum size effects in metallic nanostructures appear to be a strong driving force for self assembly. Quantum growth of Pb on Si(111) has attracted considerable attention in recent years and evidence exists that flat-topped islands with strongly preferred heights can be kinetically stabilized at moderately low temperatures because of quantum size effects. Although the electronic properties of free-standing Pb films should oscillate with bilayer periodicity, so far there has been no evidence of large-scale bilayer-by-bilayer growth on metallic or semiconducting substrates. We show that Pb films can be grown in a near-perfect bilayer growth mode on Ge(111). The films are atomically flat over macroscopic distances. Vertical step heights were also probed with STM and indicate that atomic-layer relaxations in two-dimensional thin films are substantially different from those in flat-topped islands. These films offer perfect opportunity to investigate the fundamentals of transport in relation to the quantum size effect and atomic-scale properties of thin film nanostructures. This worked is supported by the National Science Foundation under Contract No. DMR 0244570. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.
Reconstruction of modified gravity with perfect fluid cosmological models
NASA Astrophysics Data System (ADS)
Singh, C. P.; Singh, Vijay
2014-04-01
In this paper we present the cosmological viability of reconstruction of an alternative gravitational theory, namely, the modified gravity, where is the Ricci scalar curvature and the trace of stress energy momentum tensor. A functional form of is chosen for the reconstruction in perfect fluid flat Friedmann-Robertson-Walker model. The gravitational field equations contain two fluid sources, one is perfect fluid and other is due to modified gravity which is to be considered as an exotic fluid. This allows us for derivation and analysis of a set of new cosmological solutions for gravity by considering these two fluids as a non-interacting. Two known forms of scale factor (de Sitter and power-law) are considered for the explicit and successful reconstruction. The equation of state parameter (EoS) of exotic matter and the effective EoS parameter have been discussed. In de Sitter solution we find that the fluid behaves as phantom dark energy when the usual matter (perfect fluid) shows the behavior between decelerated phase to accelerated phase. In the absence of usual matter it behaves as a cosmological constant. In case of power -law cosmology two different cases are discussed and analyzed the behavior of different phases of the universe accordingly through the equation of state and density parameters.
Coherent perfect absorption in epsilon-near-zero metamaterials
NASA Astrophysics Data System (ADS)
Feng, Simin; Halterman, Klaus
2012-10-01
In conventional materials, strong absorption usually requires that the material have either high loss or a large thickness-to-wavelength ratio (d/λ≫1). We find the situation to be vastly different for bilayer structures composed of a metallic substrate and an anisotropic epsilon-near-zero (ENZ) metamaterial, where the permittivity in the direction perpendicular to its surface, ɛz, vanishes. Remarkably, perfect absorption can occur in situations where the metamaterial is arbitrarily thin (d/λ≪1) and arbitrarily low loss. Our numerical and analytical solutions reveal that under the conditions ɛz→0 and ℑ(ɛz)≫ℜ(ɛz), at perfect absorption there is a linear relationship between the thickness and the loss, which means the thickness of the absorber can be pushed to zero by reducing the material loss to zero. This counterintuitive behavior is explained in terms of coherent perfect absorption (or stimulated absorption) via critical coupling to a fast wave propagating along the ENZ layer.
Time Series Analysis Using Geometric Template Matching.
Frank, Jordan; Mannor, Shie; Pineau, Joelle; Precup, Doina
2013-03-01
We present a novel framework for analyzing univariate time series data. At the heart of the approach is a versatile algorithm for measuring the similarity of two segments of time series called geometric template matching (GeTeM). First, we use GeTeM to compute a similarity measure for clustering and nearest-neighbor classification. Next, we present a semi-supervised learning algorithm that uses the similarity measure with hierarchical clustering in order to improve classification performance when unlabeled training data are available. Finally, we present a boosting framework called TDEBOOST, which uses an ensemble of GeTeM classifiers. TDEBOOST augments the traditional boosting approach with an additional step in which the features used as inputs to the classifier are adapted at each step to improve the training error. We empirically evaluate the proposed approaches on several datasets, such as accelerometer data collected from wearable sensors and ECG data. PMID:22641699
NASA Astrophysics Data System (ADS)
Antalan, John Rafael M.
2014-06-01
Two of the oldest open problems in elementary number theory are (1) to find a quasi-perfect number and (2) to show that only numbers of the form 2k, k∈Z+ are almost perfect. A positive integer n is quasi perfect if the sum of its positive divisors σ(n) is equal to 2n + 1 where as n is almost perfect if σ(n) is equal to2n - 1. In 1951, Cattaneo showed that quasi perfect numbers cannot be even. Recently, Antalan (2013) showed that almost perfect numbers not of the form 2k must be of the form 2xb2 where x ∈ Z≥0 and b is an odd composite positive integer. Here we give sufficient non - almost perfect criterion for even positive integers ne of the form 2xb2. Particularly we show that ne is automatically not an almost perfect number if it is divisible by 2x and a prime p ≤ 2x+1 - 1. Lastly we state a problem on almost perfect numbers related to what Cattaneo did on quasi perfect number.
Geodesic matching of triangulated surfaces.
Ben Hamza, A; Krim, Hamid
2006-08-01
Recognition of images and shapes has long been the central theme of computer vision. Its importance is increasing rapidly in the field of computer graphics and multimedia communication because it is difficult to process information efficiently without its recognition. In this paper, we propose a new approach for object matching based on a global geodesic measure. The key idea behind our methodology is to represent an object by a probabilistic shape descriptor that measures the global geodesic distance between two arbitrary points on the surface of an object. In contrast to the Euclidean distance which is more suitable for linear spaces, the geodesic distance has the advantage to be able to capture the intrinsic geometric structure of the data. The matching task therefore becomes a one-dimensional comparison problem between probability distributions which is clearly much simpler than comparing three-dimensional structures. Object matching can then be carried out by an information-theoretic dissimilarity measure calculations between geodesic shape distributions, and is additionally computationally efficient and inexpensive. PMID:16900680
Matching: its acquisition and generalization.
Crowley, Michael A; Donahoe, John W
2004-01-01
Choice typically is studied by exposing organisms to concurrent variable-interval schedules in which not only responses controlled by stimuli on the key are acquired but also switching responses and likely other operants as well. In the present research, discriminated key-pecking responses in pigeons were first acquired using a multiple schedule that minimized the reinforcement of switching operants. Then, choice was assessed during concurrent-probe periods in which pairs of discriminative stimuli were presented concurrently. Upon initial exposure to concurrently presented stimuli, choice approximated exclusive preference for the alternative associated with the higher reinforcement frequency. Concurrent schedules were then implemented that gave increasingly greater opportunities for switching operants to be conditioned. As these operants were acquired, the relation of relative response frequency to relative reinforcement frequency converged toward a matching relation. An account of matching with concurrent schedules is proposed in which responding exclusively to the discriminative stimulus associated with the higher reinforcement frequency declines as the concurrent stimuli become more similar and other operants-notably switching-are acquired and generalize to stimuli from both alternatives. The concerted effect of these processes fosters an approximate matching relation in commonly used concurrent procedures. PMID:15540502
Structural color printing based on plasmonic metasurfaces of perfect light absorption
Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong
2015-06-05
Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfectmore » light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.« less
Does carbohydrate supplementation enhance tennis match play performance?
2013-01-01
Background Carbohydrate (CHO) ingestion may be an interesting approach to avoid significant decrement to the tennis match performance. The aim of the present investigation was to assess the effects of CHO supplementation on tennis match play performance. Methods Twelve young tennis players (18.0 ± 1.0 years; 176 ± 3.4 cm; 68.0 ± 2.3 kg; body fat: 13.7 ± 2.4%) with national rankings among the top 50 in Brazil agreed to participate in this study, which utilized a randomized, crossover, double blind research design. The experiment was conducted over a 5-day period in which each player completed two simulated tennis matches of a 3-hour duration. The players received either a CHO or a placebo (PLA) drinking solution during simulated tennis matches. Athlete’s performance parameters were determined by filming each match with two video cameras. Each player was individually tracked for the entire duration of the match to measure the following variables: (1) games won; (2) rally duration; (3) strokes per rally; (4) effective playing time (%); (5) aces; (6) double faults; (7) first service in; (8) second service in; (9) first return in and (10) second return in. Results There were no differences between trials in any of the variables analyzed. Conclusions CHO supplementation did not improve tennis match play performance under the present experimental conditions. PMID:24148197
Template Matching for Auditing Hospital Cost and Quality
Silber, Jeffrey H; Rosenbaum, Paul R; Ross, Richard N; Ludwig, Justin M; Wang, Wei; Niknam, Bijan A; Mukherjee, Nabanita; Saynisch, Philip A; Even-Shoshan, Orit; Kelz, Rachel R; Fleisher, Lee A
2014-01-01
Objective Develop an improved method for auditing hospital cost and quality. Data Sources/Setting Medicare claims in general, gynecologic and urologic surgery, and orthopedics from Illinois, Texas, and New York between 2004 and 2006. Study Design A template of 300 representative patients was constructed and then used to match 300 patients at hospitals that had a minimum of 500 patients over a 3-year study period. Data Collection/Extraction Methods From each of 217 hospitals we chose 300 patients most resembling the template using multivariate matching. Principal Findings The matching algorithm found close matches on procedures and patient characteristics, far more balanced than measured covariates would be in a randomized clinical trial. These matched samples displayed little to no differences across hospitals in common patient characteristics yet found large and statistically significant hospital variation in mortality, complications, failure-to-rescue, readmissions, length of stay, ICU days, cost, and surgical procedure length. Similar patients at different hospitals had substantially different outcomes. Conclusion The template-matched sample can produce fair, directly standardized audits that evaluate hospitals on patients with similar characteristics, thereby making benchmarking more believable. Through examining matched samples of individual patients, administrators can better detect poor performance at their hospitals and better understand why these problems are occurring. PMID:24588413
Transfer of the perfect flower trait from Poa secunda to Poa arachnifera
Technology Transfer Automated Retrieval System (TEKTRAN)
A Texas bluegrass (Poa arachnifera) population has been developed that successfully integrates the perfect flower trait from Poa secunda through interspecific hybridization. The resulting perfect flowered Texas bluegrass population is perennial, rhizomatous and partially apomictic in its form of re...
Adaptive Matching of the Scanning Aperture of the Environment Parameter
NASA Astrophysics Data System (ADS)
Choni, Yu. I.; Yunusov, N. N.
2016-04-01
We analyze a matching system for the scanning aperture antenna radiating through a layer with unpredictably changing parameters. Improved matching has been achieved by adaptive motion of a dielectric plate in the gap between the aperture and the radome. The system is described within the framework of an infinite layered structure. The validity of the model has been confirmed by numerical simulation using CST Microwave Studio software and by an experiment. It is shown that the reflection coefficient at the input of some types of a matching device, which is due to the deviation of the load impedance from the nominal value, is determined by a compact and versatile formula. The potential efficiency of the proposed matching system is shown by a specific example, and its dependence on the choice of the starting position of the dielectric plate is demonstrated.
From serological to computer cross-matching in nine hospitals.
Georgsen, J; Kristensen, T
1998-01-01
In 1991 it was decided to reorganise the transfusion service of the County of Funen. The aims were to standardise and improve the quality of blood components, laboratory procedures and the transfusion service and to reduce the number of outdated blood units. Part of the efficiency gains was reinvested in a dedicated computer system making it possible--among other things--to change the cross-match procedures from serological to computer cross-matching according to the ABCD-concept. This communication describes how this transition was performed in terms of laboratory techniques, education of personnel as well as implementation of the computer system and indicates the results obtained. The Funen Transfusion Service has by now performed more than 100.000 red cell transfusions based on ABCD-cross-matching and has not encountered any problems. Major results are the significant reductions of cross-match procedures, blood grouping as well as the number of outdated blood components. PMID:9704476
Adaptive Matching of the Scanning Aperture of the Environment Parameter
NASA Astrophysics Data System (ADS)
Choni, Yu. I.; Yunusov, N. N.
2016-05-01
We analyze a matching system for the scanning aperture antenna radiating through a layer with unpredictably changing parameters. Improved matching has been achieved by adaptive motion of a dielectric plate in the gap between the aperture and the radome. The system is described within the framework of an infinite layered structure. The validity of the model has been confirmed by numerical simulation using CST Microwave Studio software and by an experiment. It is shown that the reflection coefficient at the input of some types of a matching device, which is due to the deviation of the load impedance from the nominal value, is determined by a compact and versatile formula. The potential efficiency of the proposed matching system is shown by a specific example, and its dependence on the choice of the starting position of the dielectric plate is demonstrated.
Outcome analysis of factors impacting the plastic surgery match.
Wood, Jeyhan S; David, Lisa R
2010-06-01
Matching into an integrated plastic surgery program has become highly competitive. As a result it has become more difficult for both the applicants and the residency programs to determine which attributes are most important to match in plastic surgery and, more importantly, to make a surgeon who will contribute to the future of our specialty. This study was conducted to analyze potential associations between a successful match into plastic surgery and the number of interviews offered and attended, Alpha Omega Alpha (AOA) membership, and participation in away rotations. Increased competitiveness of the specialty also has required that the applicant spend significant time and money on the match process to improve his chances. Therefore, we looked at the financial impact of the interview process as well as at compliance with the new communication mandate by the Plastic Surgery Residency Review Committee designed to decrease some of the time and monetary costs associated with the match process. An anonymous 30-item survey was e-mailed to all the applicants to our institution last year. The survey consisted of questions addressing applicant profile with specific questions regarding the interview process. Descriptive statistics, including frequencies and proportions for each of the questions, were calculated. To assess the relationship between categorical outcomes, a Fisher exact test was used. Results with a P value less than 0.05 were considered to be statistically significant. Considering matching as the primary outcome measure, a statistically significant relationship was found with the number of plastic surgery interview invitations received and attended (P < 0.0001 for both), as well as with AOA membership (P = 0.018), with 89% (32/36) of the responders in AOA matching into plastic surgery. Although doing an away rotation did not have a significant association with match rate, one-third of responders matched where they did an away rotation. Gender was not found to
Villar, Alfonso Martinez, Jose Carlos; Serdio, Jose Luis de
2008-04-01
Purpose: To attempt to improve results of chemoradiation for head and neck cancer. Methods and Materials: From March 1996 to April 2007, 98 patients with head and neck cancer (15 Stage III and 83 Stage IV) were treated with a twice-daily hyperfractionated schedule. Eleven patients presented with N0, 11 with N1, 13 with N2A, 17 with N2B, 24 with N2C, and 22 with N3. Each fraction of treatment consisted of 5 mg/m{sup 2} of carboplatin plus 115 cGy with carbogen breathing. Treatment was given 5 days per week up to total doses of 350 mg/m{sup 2} of carboplatin plus 8050 cGy in 7 weeks. Anemia was corrected with erythropoietin. Results: Ninety-six patients tolerated the treatment as scheduled. All patients tolerated the planned radiation dose. Local toxicity remained at the level expected with irradiation alone. Chemotherapy toxicity was moderate. Ninety-seven complete responses were achieved. After 11 years of follow-up (median, 81 months), actuarial locoregional control, cause-specific survival, overall survival, and nodal control rates at 5 and 10 years were, respectively, 83% and 83%, 68% and 68%, 57% and 55%, and 100% and 100%. Median follow-up of disease-free survivors was 80 months. No significant differences in survival were observed between the different subsites or between the pretreatment node status groups (N0 vs. N+, N0 vs. N1, N0 vs. N2A, N0 vs. N2B, N0 vs. N2C, and N0 vs. N3). Conclusions: Improving results of chemoradiation for advanced head and neck cancer up to the level obtained with current treatments for early-stage tumors is a potentially reachable goal.
Matching Shapes Using Local Descriptors
White, R; Newsam, S; Kamath, C
2004-08-13
We present a method for comparing shapes of grayscale images in noisy circumstances. By establishing correspondences in a new image with a shape model, we can estimate a transformation between the new region and the model. Using a cost function for deviations from the model, we can rank resulting shape matches. We compare two separate distinct region detectors: Scale Saliency and difference of gaussians. We show that this method is successful in comparing images of fluid mixing under anisotropic geometric distortions and additive gaussian noise. Scale Saliency outperforms the difference of Gaussians in this context.
Graph Matching: Relax at Your Own Risk.
Lyzinski, Vince; Fishkind, Donniell E; Fiori, Marcelo; Vogelstein, Joshua T; Priebe, Carey E; Sapiro, Guillermo
2016-01-01
Graph matching-aligning a pair of graphs to minimize their edge disagreements-has received wide-spread attention from both theoretical and applied communities over the past several decades, including combinatorics, computer vision, and connectomics. Its attention can be partially attributed to its computational difficulty. Although many heuristics have previously been proposed in the literature to approximately solve graph matching, very few have any theoretical support for their performance. A common technique is to relax the discrete problem to a continuous problem, therefore enabling practitioners to bring gradient-descent-type algorithms to bear. We prove that an indefinite relaxation (when solved exactly) almost always discovers the optimal permutation, while a common convex relaxation almost always fails to discover the optimal permutation. These theoretical results suggest that initializing the indefinite algorithm with the convex optimum might yield improved practical performance. Indeed, experimental results illuminate and corroborate these theoretical findings, demonstrating that excellent results are achieved in both benchmark and real data problems by amalgamating the two approaches. PMID:26656578
Phenotype–environment matching in sand fleas
Stevens, Martin; Broderick, Annette C.; Godley, Brendan J.; Lown, Alice E.; Troscianko, Jolyon; Weber, Nicola; Weber, Sam B.
2015-01-01
Camouflage is perhaps the most widespread anti-predator strategy in nature, found in numerous animal groups. A long-standing prediction is that individuals should have camouflage tuned to the visual backgrounds where they live. However, while several studies have demonstrated phenotype–environment associations, few have directly shown that this confers an improvement in camouflage, particularly with respect to predator vision. Here, we show that an intertidal crustacean, the sand flea (Hippa testudinaria), has coloration tuned to the different substrates on which it occurs when viewed by potential avian predators. Individual sand fleas from a small, oceanic island (Ascension) matched the colour and luminance of their own beaches more closely than neighbouring beaches to a model of avian vision. Based on past work, this phenotype–environment matching is likely to be driven through ontogenetic changes rather than genetic adaptation. Our work provides some of the first direct evidence that animal coloration is tuned to provide camouflage to prospective predators against a range of visual backgrounds, in a population of animals occurring over a small geographical range. PMID:26268993
Simulation study of 'perfect lens' for near-field nanolithography
NASA Astrophysics Data System (ADS)
Guo, Xiaowei; Dong, Qiming; Liu, Yong
2011-09-01
The near-field perfect lens (NFPL) in imaging chrome gratings is investigated by using finite difference time domain (FDTD) method. The surface plasmon focused effect in and beneath the NFPL layer is demonstrated. The effects of the grating parameters and NFPL permittivity on image fidelity are explored. It is found that the excitation of surface plasmons results in frequency-increased images at large duty cycles and small imaginary part of NFPL permittivities. It is also shown that maximum intensity distributions on image plane occur at some specified pitches and duty cycles. The physics mechanisms are presented to explain these phenomena.
Quantum speed limit for perfect state transfer in one dimension
Yung, M.-H.
2006-09-15
The basic idea of spin-chain engineering for perfect quantum state transfer (QST) is to find a set of coupling constants in the Hamiltonian such that a particular state initially encoded on one site will evolve freely to the opposite site without any dynamical controls. The minimal possible evolution time represents a speed limit for QST. We prove that the optimal solution is the one simulating the precession of a spin in a static magnetic field. We also argue that, at least for solid-state systems where interactions are local, it is more realistic to characterize the computation power by the couplings than the initial energy.
The perfect storm: older adults and acute kidney injury.
Hain, Debra; Paixao, Rute
2015-01-01
Older adults have a high risk for acute kidney injury (AKI), often necessitating critical care admission. The majority of older adults live with 1 or more chronic conditions requiring multiple medications, and when faced with acute illness increased vulnerability can lead to poor health outcomes. When combined with circumstances that exacerbate chronic conditions, clinicians may witness the perfect storm. Some factors that contribute to AKI risk include the aging kidney, sepsis, polypharmacy, and nephrotoxic medications and contrast media. This paper discusses specific risks and approaches to care for older adults with AKI who are in critical care. PMID:26039649
Non-adiabatic perturbations in multi-component perfect fluids
Koshelev, N.A.
2011-04-01
The evolution of non-adiabatic perturbations in models with multiple coupled perfect fluids with non-adiabatic sound speed is considered. Instead of splitting the entropy perturbation into relative and intrinsic parts, we introduce a set of symmetric quantities, which also govern the non-adiabatic pressure perturbation in models with energy transfer. We write the gauge invariant equations for the variables that determine on a large scale the non-adiabatic pressure perturbation and the rate of changes of the comoving curvature perturbation. The analysis of evolution of the non-adiabatic pressure perturbation has been made for several particular models.
Controllable coherent perfect absorption in a composite film.
Dutta-Gupta, Shourya; Martin, O J F; Gupta, S Dutta; Agarwal, G S
2012-01-16
We exploit the versatility provided by metal-dielectric composites to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium. The slab is illuminated by coherent light from both sides, at the same angle of incidence and the conditions required for CPA are investigated as a function of the different system parameters. Our calculations clearly elucidate the role of absorption as a necessary prerequisite for CPA. We further demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion, rendering the realization of anti-lasers more flexible. PMID:22274478
Probabilistically Perfect Cloning of Two Pure States: Geometric Approach
NASA Astrophysics Data System (ADS)
Yerokhin, V.; Shehu, A.; Feldman, E.; Bagan, E.; Bergou, J. A.
2016-05-01
We solve the long-standing problem of making n perfect clones from m copies of one of two known pure states with minimum failure probability in the general case where the known states have arbitrary a priori probabilities. The solution emerges from a geometric formulation of the problem. This formulation reveals that cloning converges to state discrimination followed by state preparation as the number of clones goes to infinity. The convergence exhibits a phenomenon analogous to a second-order symmetry-breaking phase transition.
Tunable Dirac points and perfect transmission in asymmetric graphene superlattices
NASA Astrophysics Data System (ADS)
Zhang, Rui-Li; Li, Jin-Jing; Zhou, Yu; Peng, Ru-Wen; Huang, Run-Sheng; Wang, Mu
2015-08-01
We investigated the electronic band structures and transport properties in asymmetric graphene superlattices (AGSLs). Their asymmetric distribution of potentials can induce extra Dirac points (DPs) that are absent in periodic and symmetric graphene superlattices. The emergence and location of the DPs in the k space can be manipulated by selecting the special structure of the AGSL. As a result, tunable perfect transmissions are obtained in the system. Moreover, the conductance and Fano factor present interesting oscillatory behaviors. These findings may be used for the design of graphene-based electronic devices.
Perfect electromagnetic absorption at one-atom-thick scale
Li, Sucheng; Duan, Qian; Li, Shuo; Yin, Qiang; Lu, Weixin; Li, Liang; Hou, Bo; Gu, Bangming; Wen, Weijia
2015-11-02
We experimentally demonstrate that perfect electromagnetic absorption can be realized in the one-atom thick graphene. Employing coherent illumination in the waveguide system, the absorbance of the unpatterned graphene monolayer is observed to be greater than 94% over the microwave X-band, 7–13 GHz, and to achieve a full absorption, >99% in experiment, at ∼8.3 GHz. In addition, the absorption characteristic manifests equivalently a wide range of incident angle. The experimental results agree very well with the theoretical calculations. Our work accomplishes the broadband, wide-angle, high-performance absorption in the thinnest material with simple configuration.
Probabilistically Perfect Cloning of Two Pure States: Geometric Approach.
Yerokhin, V; Shehu, A; Feldman, E; Bagan, E; Bergou, J A
2016-05-20
We solve the long-standing problem of making n perfect clones from m copies of one of two known pure states with minimum failure probability in the general case where the known states have arbitrary a priori probabilities. The solution emerges from a geometric formulation of the problem. This formulation reveals that cloning converges to state discrimination followed by state preparation as the number of clones goes to infinity. The convergence exhibits a phenomenon analogous to a second-order symmetry-breaking phase transition. PMID:27258856
Extrinsic chirality: Tunable optically active reflectors and perfect absorbers
NASA Astrophysics Data System (ADS)
Plum, Eric
2016-06-01
Conventional three-dimensional (3D) chiral media can exhibit optical activity for transmitted waves, but optical activity for reflected waves is negligible. This work shows that mirror asymmetry of the experimental arrangement—extrinsic 3D chirality—leads to giant optical activity for reflected waves with fundamentally different characteristics. It is demonstrated experimentally that extrinsically 3D-chiral illumination of a lossy metasurface backed by a mirror enables tunable circular dichroism and circular birefringence as well as perfect absorption of circularly polarized waves. In contrast, such polarization phenomena vanish for conventional optically active media backed by a mirror.
Counterrotating perfect fluid discs as sources of electrovacuum static spacetimes
NASA Astrophysics Data System (ADS)
García-Reyes, Gonzalo; González, Guillermo A.
2004-11-01
The interpretation of some electrovacuum spacetimes in terms of counterrotating perfect fluid discs is presented. The interpretation is made by means of an 'inverse problem' approach used to obtain disc sources of known static solutions of the Einstein Maxwell equations. In order to do such an interpretation, a detailed study is presented of the counterrotating model (CRM) for generic electrovacuum static axially symmetric relativistic thin discs with nonzero radial pressure. Four simple families of models of counterrotating charged discs based on Chazy Curzon-type, Zipoy Voorhees-type, Bonnor Sackfield-type and charged and magnetized Darmois electrovacuum metrics are considered, where we obtain some discs with a well-behaved CRM.
Seeking perfection: a Kantian look at human genetic engineering.
Gunderson, Martin
2007-01-01
It is tempting to argue that Kantian moral philosophy justifies prohibiting both human germ-line genetic engineering and non-therapeutic genetic engineering because they fail to respect human dignity. There are, however, good reasons for resisting this temptation. In fact, Kant's moral philosophy provides reasons that support genetic engineering-even germ-line and non-therapeutic. This is true of Kant's imperfect duties to seek one's own perfection and the happiness of others. It is also true of the categorical imperative. Kant's moral philosophy does, however, provide limits to justifiable genetic engineering. PMID:17516148
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis rises from a cocoon of smoke as it rockets toward space on mission STS-106. The perfect on-time liftoff of Atlantis occurred at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis roars toward space on mission STS-106 as it lifts off in a perfect launch at 8:45:47 a.m. EDT today. On the 11-day mission to the International Space Station, the seven- member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis appears to burst forth from a cocoon of smoke in the Florida marsh lands as it rockets toward space on mission STS-106. The perfect on-time liftoff of Atlantis occurred at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbe d is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Billows of clouds and smoke frame Space Shuttle Atlantis after a perfect on-time launch on mission STS-106 at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven- member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
A perfect on-time launch for Atlantis as it rockets toward space on mission STS-106. Liftoff occurred at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven- member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis appears to burst forth from a cocoon of smoke as it rockets toward space on mission STS-106. The perfect on-time liftoff of Atlantis occurred at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven- member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis streaks into the sky on mission STS-106 after a perfect on-time launch at 8:45:47 a.m. EDT. Blue mach diamonds are barely visible behind the main engine nozzles. On the 11-day mission to the International Space Station, the seven- member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbe d is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Filling the ground with billows of smoke and steam created by the flaming solid rocket boosters, Space Shuttle Atlantis speeds toward space on mission STS-106. The perfect on-time liftoff occurred at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbe d is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
A perfect launch sends Space Shuttle Atlantis, leaving a trail of flames and billows of smoke and clouds behind, hurtling toward space on mission STS-106. Liftoff occurred at 8:45:47 a.m. EDT today. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
Space Shuttle Atlantis clears the tower as it roars into space on mission STS-106 after a perfect on-time launch at 8:45:47 a.m. EDT. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A perfect launch of Atlantis on mission STS-106
NASA Technical Reports Server (NTRS)
2000-01-01
After a perfect on-time launch on mission STS-106 at 8:45:47 a.m. EDT, Space Shuttle Atlantis rolls and displays its external tank and solid rocket boosters. On the 11-day mission to the International Space Station, the seven-member crew will perform support tasks on orbit, transfer supplies and prepare the living quarters in the newly arrived Zvezda Service Module. The first long-duration crew, dubbed '''Expedition One,''' is due to arrive at the Station in late fall. Landing of Atlantis is targeted for 4:45 a.m. EDT on Sept. 19.
A quantum model of almost perfect energy transfer
NASA Astrophysics Data System (ADS)
Alicki, Robert; Giraldi, Filippo
2011-08-01
The Wigner-Weisskopf-type model describing the energy transfer between two centres mediated by a continuum of energy levels is studied. This work is motivated by the recent interest in transport phenomena at nanoscale in biology and quantum engineering. The analytical estimation for the energy transfer efficiency is derived in the weak coupling regime and the conditions for the almost perfect transfer are discussed. The embedding of the standard tight-binding model into the Wigner-Weisskopf one which includes the environmental noise is presented.